5. Reduction in Single Surface Results from Pre to Immediate Post Intervention Similar to the composite dust sample results, when single surface sample pre to immediate postintervention dust lead loading results were compared, substantial median percent decreases and median µ g/ ft2 decreases were observed for bare floors, interior window sills and window troughs. These reductions were most dramatic for window sills and troughs and were particularly large in the LHR+ W units ( see Tables 15 and 16 on pages 43 and 44, respectively, and Figure 8 on page 45). For each of these surface types, the median percent decrease for LHR+ W units was greater than that for LHR units. The association between the median percent reduction in single surface dust lead loadings and the assigned treatment group was highly significant for interior window sills and troughs ( p values= 0.0001 and 0.0057, respectively) but was not significant for bare floors ( p value= 0.1655).

When reductions for LHR and LHR+ W units were compared with reductions for Baltimore Round One HUD Evaluation units, the Round One units had statistically significant larger decreases for all three surface types, as measured by median percentage and actual µ g/ ft2, than did both LHR and LHR+ W units ( p value= 0.0001 for all three surface types). 11/ 23/ 05 43 Table 15: Percent Reduction in Pre to Immediate Post Intervention Single Surface Dust Lead Loadings Surface Type and Statistic Single Surface Dust Samples LHR Units Pre to Immediate Post Intervention Percent Reduction LHR+ W Units Pre to Immediate Post Intervention Percent Reduction Baltimore HUD Unitsa Pre to Immediate Post Intervention % Reduction Bare floors ( 16 LHR, 63 LHR+ W) b: 25th Percentile Percent Decrease Median Percent Decrease 75th Percentile Percent Decrease 24 70 97 62 88 98 86 95 98 Interior window sills ( 16 LHR, 62 LHR+ W) b: 25th Percentile Percent Decrease Median Percent Decrease 75th Percentile Percent Decrease 55 84 95 96 99 > 99 98 > 99 > 99 Window troughs ( 16 LHR, 62 LHR+ W) b: 25th Percentile Percent Decrease Median Percent Decrease 75th Percentile Percent Decrease 82 94 98 96 99 > 99 95 99 > 99 Source: Form 04B aBaltimore HUD unit data are Round I data from the National Evaluation of HUD's Lead Hazard Control Grant Program and were compiled using initial Phase 2 data ( immediate post intervention) for units that were vacant at pre intervention and at immediate post intervention. For floors, Baltimore HUD unit data include both interior floor and entry floor data. bBased on Wilcoxon rank sum tests, the association between the median percent reduction in single surface dust lead loadings and assigned treatment group was significant for sills ( p= 0.0001) and troughs ( p= 0.0057), but not significant for bare floors ( p= 0.1655). cBased on Wilcoxon rank sum tests, Baltimore Round 1 units had statistically significant larger median percent decreases in dust lead loadings than did study units in either treatment group ( p= 0.0001 for all 3 surface types). 11/ 23/ 05 44 Table 16: Micrograms Per Square Foot Reduction in Pre to Immediate Post Intervention Single Surface Dust Lead Loadings Surface Type and Statistic Single Surface Dust Samples LHR Units Pre to Immediate Post Intervention µ g/ ft2 Reduction LHR+ W Units Pre to Immediate Post Intervention µ g/ ft2 Reduction Baltimore HUD Units Pre to Immediate Post Intervention µ g/ ft2 Reduction Bare floors ( 16 LHR, 63 LHR+ W): 25th Percentile µ g/ ft2 Decrease Median µ g/ ft2 Decrease 75th Percentile µ g/ ft2 Decrease 5 99 3,027 97 226 971 98 265 618 Interior window sills ( 16 LHR, 62 LHR+ W): 25th Percentile µ g/ ft2 Decrease Median µ g/ ft2 Decrease 75th Percentile µ g/ ft2 Decrease 70 497 9,102 752 2,516 8,598 800 2,492 7,124 Window troughs ( 16 LHR, 62 LHR+ W): 25th Percentile µ g/ ft2 Decrease Median µ g/ ft2 Decrease 75th Percentile µ g/ ft2 Decrease 998 4,111 36,239 1,640 12,022 131,245 1,020 3,591 12,994 Source: Form 04B 1Baltimore HUD unit data are Round I data from the National Evaluation of HUD's Lead Hazard Control Grant Program and were compiled using initial Phase 2 data ( immediate post intervention). For floors, Baltimore HUD unit data include both interior floor and entry floor data. 11/ 23/ 05 45 Figure 8: Pre and Immediate Post Intervention Single Surface Dust Lead Loading for LHR and LHR+ W Units ( Logarithmic Scale)

1 10 100 1000 10000 100000 1000000 Pre Int.

Post Int.

Pre Int.

Post Int.

Pre Int.

Post Int.

Pre Int.

Post Int.

Pre Int.

Post Int.

Pre Int.

Post Int.

LHR LHR+ W LHR LHR+ W LHR LHR+ W Bare Floors Window Sills Window Troughs Dust Lead Loading ( ug/ ft^ 2)

Note: Bottom whisker= 5th percentile; top whisker= 95th percentile; box= 25th & 75th percentile; circle= median; triangle = geometric mean.

6. Units Having an Increase in Single Surface Dust Lead Loadings from Pre to Immediate Post Intervention Despite the significant median decreases in dust lead loadings between pre and immediate postintervention data in Table 17 on page 46 show that some units experienced increases in single surface dust lead loadings between these two phases. The percentage of LHR+ W units that underwent an increase was generally lower than that of LHR units and was comparable to that of Baltimore HUD units. 11/ 23/ 05 46 Table 17: Number and Percent of Units Having an Increase in Single Surface Dust Lead Loadings from Pre to Immediate Post Intervention Surface Type and Sample Type LHR LHR+ W Baltimore HUD Units Bare Floors: 4/ 16 ( 25%) 4/ 63 ( 6%) 12/ 278 ( 4%)

Interior window sills: 2/ 16 ( 12%) 1/ 62 ( 2%) 2/ 277 ( 1%)

Window Troughs: 2/ 16 ( 12%) 1/ 62 ( 2%) 13/ 273 ( 5%)

7. Comparison of Immediate Post Intervention Single Surface Results with Clearance Standards/ Guidance Under the lead hazard reduction treatment option of EA 6 8, enrolled LHR and LHR+ W units were only required to pass a visual inspection performed by an independent visual inspector; collection of post treatment dust samples and comparison of such results to clearance standards were not required. However, this study considered clearance dust standards set by Maryland and by HUD/ EPA to assess the extent to which prescribed treatments produced dust results that were sufficient for safe occupancy of treated units and to help determine whether the prescribed independent visual inspection procedure provided a sufficient level of lead hazard reduction. This comparison to clearance standards is not required by EA 6 8 and was performed in this study for research purposes only.

If such testing had been required, for single surface floor dust samples, 35 percent of the LHR units and 25 percent of the LHR+ W units had at least one floor sample that would have " failed" the Maryland standard of 200 µ g/ ft2 ( see Table 18 on page 47). Sixty ( 60) percent of the LHR units and 41 percent of the LHR+ W units had at least one floor sample that would have " failed" the HUD/ EPA 1995 guidance7 of 100 µ g/ ft2. Assigned treatment group was not significantly associated with a unit " passing" or " failing" either of these two clearance standards ( pvalues 0.4 and 0.14 for clearance standards of 200 and 100 µ g/ ft2, respectively). These are generally higher " failure" rates than the 29 percent initial floor failure rate observed for vacant Baltimore Round I units enrolled in the National Evaluation. 8 7 HUD/ EPA guidance values of 100 µ g/ ft2 for floors, 500 µ gft2 for window sills, and 800 µ g/ ft2 for window troughs were in effect during the study period. New standards that became effective in September 2000 ( 40, 250, and 400 µ g/ ft2 were not in effect when immediate post intervention data were collected and are therefore not discussed in this report. 8 Clearance failure rates for Baltimore HUD units are based on initial clearance testing conducted after treatment, comparing results with floor, sill and trough standards of 100, 500 and 800 µ g/ ft2, respectively. 11/ 23/ 05 47 Table 18: Immediate Post Intervention Single Surface " Clearance Failures"   Floors Immediate Post Intervention Single Surface Dust Sample Results   FLOOR " Clearance Failures" a LHR ( 20 units total) LHR+ W ( 63 units total) All Units ( 83 units total)

# units (%)

100 µ g/ ft2 12 ( 60%) 26 ( 41%) 38 ( 46%)

# units (%)

200 µ g/ ft2 7 ( 35%) 16 ( 25%) 23 ( 28%)

aClearance " failure" was not significantly associated with assigned treatment group ( p= 0.403 and p= 0.143 for clearance stds of 200 and 100 µ g/ ft2, respectively)

For single surface interior window sill dust samples, replacement of windows in the LHR+ W units resulted in fewer " clearance failures" ( see Table 19). If clearance testing had been required, 20 percent of the LHR units and five percent of the LHR+ W units had at least one sill sample that would have " failed" the Maryland and HUD/ EPA guidance of 500 µ g/ ft2. Assigned treatment group was significantly associated with post intervention interior window sill dust lead loadings " passing" or " failing" at 500 µ g/ ft2 ( p value= 0.035). These rates are higher than the one percent sill initial failure rate observed for vacant Baltimore Round I units enrolled in the National Evaluation. 8 Table 19: Immediate Post Intervention Single Surface " Clearance Failures"   Interior Window Sills Immediate Post Intervention Single Surface Dust Sample Results   INTERIOR WINDOW SILL " Clearance Failures" a LHR ( 20 units total) LHR+ W ( 62 units total) All Units ( 82 units total)

# units (%)

500 µ g/ ft2 4 ( 20%) 3 ( 5%) 7 ( 8%)

aClearance " failure" was significantly associated with assigned treatment group ( p= 0.035).

Again, for single surface window trough dust samples, replacement of windows in the LHR+ W units resulted in a lower percentage of " clearance failures" ( see Table 20 on page 48). Had clearance testing been required, 50 percent of the LHR units and 19 percent of the LHR+ W units had at least one trough sample that would have " failed" the Maryland and HUD/ EPA guidance standard of 800 µ g/ ft2. Assigned treatment group was significantly associated with postintervention window trough dust lead loadings " passing" or " failing" this standard ( pvalue 0.007). These rates are higher than the six percent initial trough failure rate noted for Baltimore Round I units. 8 11/ 23/ 05 48 Table 20: Immediate Post Intervention Single Surface " Clearance Failures"   Window Troughs Immediate Post Intervention Single Surface Dust Sample Results   WINDOW TROUGH " Clearance Failures" a LHR ( 20 units total) LHR+ W ( 62 units total) All Units ( 82 units total)

# units (%)

800 µ g/ ft2 10 ( 50%) 12 ( 19%) 22 ( 27%)

aClearance " failure" was significantly associated with assigned treatment group ( p= 0.007).

B. Results of Immediate Post Intervention Visual Assessments As required in EA 6 8, each of the 121 units was independently inspected and passed the required visual inspection after the prescribed treatments were completed. As one of the evaluation measures of this study, LAAP inspectors performed a separate, confirmatory visual assessment ( not related to the property owner's statutory requirement for an independent visual inspection) in each unit to determine if any visible treatment " failures" could be detected. For the purposes of this study, a treatment " failure" was defined as an observation by the LAAP inspector that one or more of the ten lead hazard reduction treatments prescribed in the statute had not been fully completed. The Maryland statute did not specify a " de minimis" level above which the treatment was considered a " failure;" therefore, any observable deficient or missing treatment was classified as a " failure."

A complete list of immediate post intervention visual assessment " failures" is presented in Appendix G. Table 21 on page 49 presents the distribution of treatment " failures" per unit. There were no units having more than 5 " failures." Notably, the LAAP inspectors found that 51 of the 57 LHR units ( 89 percent) and 60 of the 64 ( 94 percent) of the LHR+ W units " failed" the confirmatory visual assessment for at least one item. This equates to an overall visual assessment " failure" rate of 92 percent for the 121 study units. The owner corrected treatment " failures" noted during the immediate post intervention sampling visit before tenants moved in. These corrections were " validated" by LAAP inspectors, who required owners and/ or contractors to complete their work prior to payment.

Overall, the likelihood of LHR units having one or more " failures" was almost the same as that of the LHR+ W units. The mean number of " failure" types per unit for LHR units ( 2.1) was significantly different and higher than that for LHR+ W units ( 1.7) ( p value= 0.0255). If only " failure" types applicable to both treatment groups are considered, LHR units have slightly more mean " failures" ( 1.8) than LHR+ W units ( 1.6). However, this difference is not significant ( pvalue 0.1389). 11/ 23/ 05 49 Table 21: Number of Immediate Post Intervention Visual Assessment " Failures" Per Unit Number of Immediate Post Intervention Visual Assessment " Failures" Per Unita ( 57 LHR units, 64 LHR+ W units) LHR # Units (% Units) LHR+ W # Units (% Units) All Units # Units (% Units)

" 0" lead hazard treatment " failures" 6 ( 10%) 4 ( 6%) 10 ( 8%) " 1" lead hazard treatment " failure" 7 ( 12%) 26 ( 41%) 33 ( 27%) " 2" lead hazard treatment " failures" 22 ( 39%) 21 ( 34%) 44 ( 36%) " 3" lead hazard treatment " failures" 19 ( 33%) 9 ( 14%) 28 ( 23%) " 4" lead hazard treatment " failures" 2 ( 4%) 3 ( 5%) 5 ( 4%) " 5" lead hazard treatment " failures" 1 ( 2%) 0 ( 0) 1 ( 1) Source: Form 05 aThe mean number of " failures" per unit ( 2.1 for LHR units; 1.7 for LHR+ W units) was significantly associated with assigned treatment group ( p= 0.0255).

1. Types of Immediate Post Intervention " Failures"

The most common " failure" was that not all paint was intact after completion of the prescribed lead hazard reduction treatments ( i. e., chipping, flaking and/ or peeling paint remained) ( see Table 22 on page 50). Almost 75 percent of all units ( 77 percent of the LHR units and 73 percent of the LHR+ W units) exhibited evidence of this " failure" type. Almost 40 percent of all units ( 44 percent of the LHR units and 33 percent of the LHR+ W units) had evidence of visible paint chips and/ or debris remaining. It should be noted that the areal density ( i. e., depth) and the lead concentration of the chips/ debris were not measured. In 43 percent of all units ( 49 percent of the LHR units and 38 percent of the LHR+ W units), the treatment " failure" of doors with painted surfaces continuing to rub together or bind was observed. In 26 percent of the LHR units, the window trough material ( e. g., vinyl or metal) was not properly attached. Other treatment " failure" types were much less prevalent. None of the ten types of treatment " failures" were significantly associated with treatment group based on chi square testing. 11/ 23/ 05 50 Table 22: Immediate Post Intervention Visual Assessment for Lead Hazard Reduction Treatment " Failures" Type of Immediate Post Intervention Visual Assessment " Failures" a ( 57 LHR units, 64 LHR+ W units) LHR # Units (% Units) LHR+ W # Units (% Units) All Units # Units (% Units)

Not all paint intact ( chipping, peeling or flaking paint remains) 44 ( 77%) 47 ( 73%) 91 ( 75%)

Visible structural defect that could cause paint deterioration remains 1 ( 2%) 2 ( 3%) 3 ( 2%)

If sills stripped/ repainted or replaced, not all treatments in place 2 ( 4%) 6 ( 9%) 8 ( 7%)

If sills encapsulated with vinyl, metal, etc., not all material is properly attachedb 0 ( 0%) 1 ( 2%) 1 ( 1%)

If troughs capped with vinyl, metal, etc., not all material is properly attachedb 15 ( 26%) N/ Ac 15 ( 12%) d For windows, not all top sashes are fixed in place 0 ( 0%) N/ Ac 0 ( 0) d For doors, painted surfaces continue to rub together 28 ( 49%) 24 ( 38%) 52 ( 43%)

Some bare floors are not smooth and cleanable 2 ( 4%) 4 ( 6%) 6 ( 5%)

Not all kitchen and bathroom floors are overlaid with water resistant coverings 4 ( 7%) 4 ( 6%) 8 ( 7%)

Visible paint chips or debris remains 25 ( 44%) 21 ( 33%) 46 ( 38%)

Source: Form 05 aNone of these " failure" types were significantly associated with the assigned treatment group ( p values vary from 0.1949 to 0.633). bProperly attached is defined as correctly installed, with caps held firmly in place with a sufficient number of fittings ( e. g., nails) and with caulking completed. cIn LHR+ W units, these treatments were not necessary by virtue of the installation of new vinyl replacement windows with unpainted top sashes and troughs. dBoth values are understated due to the inapplicability of these treatments for LHR+ W units.

The geometric means of " failures" presented in Table 23 on page 51 were calculated by first summing, within a unit, all reports of a particular " failure" type having the same measurement units ( e. g., ft2), then calculating the geometric mean across dwelling units. These data indicate that problems recorded by LAAP inspectors were easily observed. For example, LAAP inspectors reported a dwelling unit geometric mean of 1 ft2 of non intact paint in both LHR and LHR+ W units at immediate post intervention. This type of " failure" was reported 63 times in 31 LHR units, and reported 78 times in 34 LHR+ W units, indicating that this was a widespread and large problem. " Visible paint chips and debris remaining" at Phase 2 was also a extensive problem; a geometric mean of 8 ft2 of visible chips remained in LHR units and 16 ft2 remained in LHR+ W units, with this " failure" being reported 29 times in 19 LHR units, and 48 times in 21 LHR+ W units. As previously noted, the areal density ( i. e., depth) and the lead concentration of these chips/ debris were not measured. " Painted door surfaces rubbing together" was reported 40 times in 28 LHR units and 38 times in 24 LHR+ W units, with at least one door noted as a problem in each report. The status of floors at Phase 2 was generally less widely reported but 11/ 23/ 05 51 nonetheless noteworthy, with a geometric mean of 4 ft2 of bare floors in LHR units and 2 ft2 in LHR+ W units remaining not smooth and cleanable. A geometric mean of 2 ft2 of kitchen or bathroom floors in LHR units and 1 ft2 in LHR+ W units were reportedly not overlaid with waterresistant coverings at immediate post intervention.

Table 23: Reporting Frequency of Specified Types of Treatment " Failures" at Immediate Post Intervention LHR LHR+ W " Failure" Type ( 57 LHR, 64 LHR+ W) Unit of Measure # Units with Specified " Failure " Rpt'd Reporting Freq. of " Failure" Type at Ph 2 " Failure" Magnit. ( geom. mean & 95% Conf Limits) # Units with Specified " Failure " Rpt'd Reporting Freq. of " Failure" Type at Ph 2 " Failure" Magnit. ( geom. mean & 95% Conf Limits) EAa 8 19 2 ( 1, 6) 1 1 1c LF 16 30 2 ( 1, 4) 20 27 1 ( 1, 2) Not all paint intact ( 44 LHR, 47 LHR+ W) SF 31 63 1 ( 0.2, 1) 34 78 1 ( 0.4, 3)

For doors, painted surfaces continued to rub together ( 28 LHR, 24 LHR+ W) EAa 28 40 1 ( 1, 2) 24 38 1 ( 1, 2)

Some bare floors not smooth & cleanable ( 2 LHR, 4 LHR+ W) SF 2 5 4c 4 8 2c Not all kitchen & bathroom floors overlaid with water resistant coverings ( 4 LHR, 4 LHR+ W) SF 4 4 2 ( 1, 4) 4 4 1c EAb 6 25 4 ( 2, 13) 1 1 2c LF 4 10 21c 0 0  Visible paint chips or debris remains ( 25 LHR, 21 LHR+ W) SF 19 29 8 ( 3, 19) 21 48 16 ( 6, 42)

EA= each; LF= linear foot; SF= square foot aFor these " failure" types, " each" denotes window components ( e. g., upper sash, lower sash), door casings, or handrails in need of re painting. LF/ SF values are not available for these occurrences. bFor these " failure" types, " each" denotes a window in need of re cleaning. cNo 95% confidence limits were calculated due to the small number of units having this failure reported. 11/ 23/ 05 52 2. Number of Rooms with " Failures" at Phase II In general, two to three rooms per unit had treatment " failures;" few units had " failures" in only one room or in more than four rooms ( see Figure 9).

Figure 9: Percentage of Units Having Specified Number of Rooms Per Unit with Immediate Post Intervention Visual Assessment " Failures"

10%

9% 16% 21% 21%

11%

4%

2% 4%

0% 4% 6% 17% 28%

23%

12%

3% 3% 3% 3%

0% 0%

0% 5% 10% 15% 20% 25% 30%

0 1 2 3 4 5 6 7 8 9 10 Percentage of Units Having Specified Number of Rooms with Visual Assessment Treatment " Failures" at Immediate Post Intervention Percentage of Units LHR Units LHR+ W Units In the 57 LHR units, considering only those rooms with " failures" that are applicable to both LHR and LHR+ W units, the mean number of rooms with lead hazard control treatment " failures" was 3.1 rooms per unit, against a mean total number of 6.6 rooms per unit. In the 64 LHR+ W units, the mean number of rooms with " failures" was 2.6 rooms, against a mean total number of 6.7 rooms per unit. This mean number of rooms with prescribed treatment " failures" was not significantly associated with the assigned treatment group ( p value= 0.206). Table 24 on page 53 presents data on the mean number of rooms per unit with a given " failure" type.

3. Type of Contractor and Number of " Failures" at Immediate Post Intervention For profit contractors, the property owner/ employees or non profit contractors performed lead hazard reduction treatments. ( Only five units were treated by non profit contractors; therefore, these data are excluded from the study.) For LHR units, the mean number of " failures" per unit for for profit contractor treated units and property owner/ employee treated units were 3.3 and 5.5, respectively ( see Table 25 on page 53). For LHR+ W units, the mean numbers of " failures" per unit for for profit contractors and property owners/ employees treated units were 3.1 and 3.0, respectively. There was no significant association between the mean number of " failures" per unit and the contractor type based on a Fisher's Exact Test ( p value= 0.4823). 11/ 23/ 05 53 Table 24: Mean Number of Rooms Per Unit with Specified Immediate Post Intervention Visual Assessment " Failures" by Treatment Groupa Type of Immediate Post Intervention Visual Assessment " Failures" ( 57 LHR units, 64 LHR+ W units) LHR Mean # Rooms Per Unit ( 95% Conf. Int.) LHR+ W Mean # Rooms per Unit ( 95% Conf. Int.) Not all paint intact ( chipping, peeling or flaking paint remains) 1.7 ( 1.4; 2.1) 1.4 ( 1.1; 1.7) Visible structural defect that could cause paint deterioration remains 0.02 ( 0; 0.05) 0 ( 0; 0.08) If sills stripped/ repainted or replaced, not all treatments in place 0.05 ( 0; 0.11) 0.2 ( 0.07; 0.3) If sills encapsulated with vinyl, metal, etc., not all material is property attached 0 0 If troughs capped with vinyl, metal, etc., not all material is properly attached 0.5 ( 0.35; 0.7) N/ Ab For windows, not all top sashes are fixed in place 0 N/ Ab For doors, painted surfaces continue to rub together 0.7 ( 0.5; 0.9) 0.6 ( 0.4; 0.8) Some bare floors are not smooth and cleanable 0.09 ( 0.01; 0.2) 0.1 ( 0; 0.2) Not all kitchen and bathroom floors are overlaid with water resistant coverings 0.07 ( 0; 0.1) 0.1 ( 0; 0.1) Visible paint chips or debris remains 1.1 ( 0.8; 1.4) 0.7 ( 0.5; 1.0) Source: Form 05 aMean number of rooms with prescribed treatment " failures" was not significantly associated with the assigned treatment group ( p= 0.206). bIn LHR+ W units, these treatments were not necessary by virtue of the installation of new vinyl replacement windows with unpainted top sashes and troughs.

Table 25: Mean Number of Immediate Post Intervention " Failures" per Unit by the Type of Contractora, b Mean Number of Immediate Post Intervention " Failures" per Unit Contractor Type LHR Units LHR+ W Units For profit contractor 3.3 3.1 Property owner/ employees 5.5 3.0 Source: Form 05 a Because only a limited number of LHR and LHR+ W units ( i. e., five combined) had nonprofit contractors performing the work, the number of " failures" is not easily compared against for profit contractors and property owner/ employees work. Therefore, nonprofit contractor data are not presented in this table. bThe mean number of " failures" per unit and contractor type were not significantly associated ( p= 0.4823). 11/ 23/ 05 54 C. Description of and Factors Affecting Costs Various cost data were collected during the study, including the LAAP approved costs for the prescribed lead hazard reduction treatments, plus the additional window replacement costs for the LHR+ W units. The study also collected owner estimated turnover costs that would have been incurred even if the enrolled units had not been subject to the EA 6 8 risk reduction requirements. However, because these latter data were based on interviews with property owners and/ or their representatives, they are considered highly subjective and were excluded from this study. Finally, the study determined what type of contractor ( e. g., for profit, nonprofit or property owner/ employee) performed the work and whether any concurrent work ( e. g., roof, plumbing and electrical repairs) was completed in addition to the lead related treatments.

The costs presented in this section are those considered to be solely associated with EA 6 8 prescribed treatments. In other words, measures that are not otherwise contained in existing housing code provisions and/ or part of a normal rental unit turnover regimen would be included when determining the incremental cost of complying with the statute. The measures that are considered unique to EA 6 8 include:

  Stripping and repainting, replacing or encapsulating all interior window sills with vinyl, metal or any other material;   Ensuring that caps of vinyl, aluminum or other material are installed in all window troughs in order to make the window troughs smooth and cleanable;   Except for a treated or replacement window that is free of lead based paint on its friction surfaces, fixing the top sash of all windows in place in order to eliminate the friction caused by movement of the top sash;   Re hanging all doors necessary in order to prevent the rubbing together of a lead painted surface with another surface;   Making all bare floors smooth and cleanable; and   HEPA vacuuming and washing of the interior of the affected property with high phosphate detergent or its equivalent.

Depending on the nature of certain bathroom and kitchen floor repairs, another EA 6 8 prescribed treatment that might or might not be considered extra cost is ensuring that all kitchen and bathroom floors are overlaid with a smooth, water resistant covering.

As discussed in Section II. B, participating property owners received up to 80 percent of their full lead hazard control costs from LAAP in the form of a loan/ grant, subject to a spending cap of $ 10,000. The remaining 20 percent was self funded. LAAP funding was provided through the HUD Round III Lead Hazard Control Grant. However, as part of this study and in order to determine the incremental cost of complying with EA 6 8, LAAP inspectors reviewed and revised the owners' original lead hazard reduction costs by subtracting cost items that could be considered code related and/ or part of normal unit turnover. The most notable of these is painting, which was often the largest single cost element. ( See Appendix H for the gross lead hazard reduction costs, 80 percent of which were reimbursed by LAAP, and the estimated EA 6 8 lead hazard reduction treatment costs for each of the enrolled units.) 11/ 23/ 05 55 Based on the LAAP inspectors' estimated EA 6 8 lead hazard reduction treatment cost calculations, the median cost for completing the prescribed treatments in LHR units was $ 2,154, while for LHR+ W the median cost was $ 1,649. The LHR units' median cost is likely higher than the LHR+ W units' median cost because LHR unit costs included the expense of the prescribed window treatments, while window replacement expenses for LHR+ W units were calculated separately ( see Table 26). However, the median total lead cost for LHR+ W units ($ 4,348) was over twice that for LHR units ($ 2,154), reflecting the added expense of window replacement.

T able 26: Description of Lead Hazard Reduction Costs Lead Hazard Reduction Intervention Costs and Window Replacement Costs ( 57 LHR units, 64 LHR+ W units) LHR 5th Percentile 25th Percent. Median 75th Percent. 95th Percent. LHR+ W 5th Percentile 25th Percent. Median 75th Percent. 95th Percent.

Cost of lead hazard reduction treatments only $ 820 $ 1,462 $ 2,154 $ 3,015 $ 3,920 $ 773 $ 1,168 $ 1,649 $ 2,212 $ 3,036 Cost of window replacement only N/ A N/ A N/ A N/ A N/ A $ 1,625 $ 2,200 $ 2,600 $ 3,185 $ 4,200 Total Lead Costs ( lead hazard reduction treatments and, if applicable, window replacement) $ 820 $ 1,462 $ 2,154 $ 3,015 $ 3,920 $ 2,589 $ 3,750 $ 4,348 $ 5,173 $ 6,458 Source: Form 05 Interestingly, when analyzing costs against the type of contractor performing the lead hazard reduction treatments, for profit contractors' mean costs were slightly higher than property owner/ employees' mean costs in LHR units, but lower in LHR+ W units ( see Table 27 on page 56). 11/ 23/ 05 56 Table 27: Mean Lead Hazard Reduction Costs by Contractor Typea Contractor Type ( 56 LHR, 64 LHR+ W) LHR Mean Cost ( std. deviat.) b LHR+ W Mean Cost ( std. deviat. ) b For profit contractor ( 27 LHR, 32 LHR+ W) $ 2,405 ( 1,196 ) $ 4,277 ( 1,309 ) Property owner/ employees ( 28 LHR, 28 LHR+ W) $ 2,214 ( 770 ) $ 4,639 ( 1,106 ) Source: Form 05 aBecause only a limited number of LHR and LHR+ W units ( i. e., five combined) had nonprofit contractors performing the work, the costs are not easily compared against for profit contractor and property owner/ employee work. Therefore, nonprofit contractor data are not presented in this table. b Mean costs for LHR units were calculated using only the cost of prescribed lead hazard reduction treatments, while those for LHR+ W units also included additional costs associated with window replacement.

In the LHR+ W units, an average of nine ( 9) to 10 windows were replaced. ( As previously noted, this replacement was not part of the lead hazard reduction treatments required by the statute.) Replacement windows were typically double hung, thermo pane vinyl units; existing window jambs and exterior casing were usually wrapped with aluminum coil stock and any remaining painted components were stabilized and repainted. The median cost per window replacement was $ 275, with a minimum recorded cost per window of $ 220 and a maximum recorded cost per window of $ 357. Additional ( i. e., concurrent) work was performed in 17 of 57 LHR units ( 29.8 percent) and 27 of 64 LHR+ W units ( 42.2 percent). This work included roofing, plumbing, heating and electrical repairs and replacement of other fixtures and components.

For the 57 LHR units, the mean number of days to complete the intervention was 57.8 days. For the 64 LHR+ W units, the mean number of days to complete the intervention was 56.5 days. These relatively long periods reflect the fact that many property owners/ employees who performed their own work, and some for profit and nonprofit contractors, worked intermittently over time for various reasons. Therefore, these mean numbers are not representative of the actual uninterrupted time that would have been needed to complete the prescribed lead hazard reduction treatments.

D. Description of Statistical Modeling Through Immediate Post Intervention 1. Predicting Dust Lead Loading at Immediate Post Intervention A multiple regression model with backward elimination9 was run to identify which factors would be significant predictors of immediate post intervention dust lead loadings. A separate model was run for each surface type ( i. e., bare floors, interior window sills and window troughs). The dwelling unit average of single surface samples for each surface type was the dependent variable in each model. Dust lead loading measurements were log transformed. ( Tables of statistical results from these models are provided in Appendix I.)

9 In a multiple regression model with backward elimination, all possible predictors of the outcome are initially entered into the model. Then hypothesis tests are run to determine if any factors can be removed from the predictive equation when the other factors are retained. The least significant factor ( i. e., the factor with the largest observed significance level) is removed, and the process is repeated to determine if more factors can be dropped. 11/ 23/ 05 57 The set of possible predictors considered were:

  Type of building ( e. g., rowhouse, more than four units in a building, single detached, etc.);   Year of construction ( e. g., pre 1910, 1910 1919, 1920 1929, etc.);   Contractor type ( i. e., for profit, nonprofit, property owner/ employee);   Concurrent work ( i. e., yes or no);   Treatment group ( i. e., LHR or LHR+ W);   Pre intervention dwelling unit average of single surface samples dust lead loading results for a given surface type ( i. e., bare floors, interior window sills or window troughs);   Number of items of interior dwelling unit deterioration ( 0 4);   Number of items of exterior building deterioration ( 0 6);   Percent of windows replaced out of the total number of windows in a dwelling unit;   Market value of a dwelling unit ($);   Total lead hazard reduction cost for a dwelling unit, including window replacement costs, if applicable ($); and   Interactions of ( 1) the number of interior dwelling unit deterioration items, ( 2) the number of exterior building deterioration items, and ( 3) pre intervention dust lead loadings with each of the following: concurrent work, percent of windows replaced, total lead hazard reduction cost, and assigned treatment group.

( Note: The relationship between components of the visual assessment and immediate postintervention dust lead loading results was assessed and found to be non significant in every case. Hence, these variables were not included in the models.)

On bare floors, the entire set of possible predictors did not significantly predict immediate postintervention floor dust lead loading ( p value= 0.4687). On interior window sills, the variables found to predict immediate post intervention dust loading were pre intervention interior window sill dust lead loading and treatment group. The percentage of variation accounted for in immediate post intervention dust lead loading by these two variables ( i. e., R2) is 27 percent. On window troughs, the variables found to predict immediate post intervention dust lead loading were pre intervention window trough dust lead loading and treatment group. The percentage of variation accounted for in immediate post intervention dust lead loading by these two variables ( i. e., R2) is 26 percent.

2. Predicting Dust Lead Loading " Failures" at Immediate Post Intervention Separate logistic regression models with backward elimination were employed to predict whether dwelling units would have clearance " failures" on bare floors, interior window sills and window troughs based on standards of 100 µ g/ ft2, 500 µ g/ ft2, and 800 µ g/ ft2, respectively ( see Appendix I). In a logistic model, the outcome of interest is a binary response variable such as " pass/ fail." The same set of possible predictors that were used in predicting dust lead loading at immediate post intervention were also employed for this model, except that interactions were not included ( not appropriate for logistic models).

Clearance " failure" on bare floors was not modeled since no relationship was found when attempting to predict floor dust lead loading at immediate post intervention. On interior window 11/ 23/ 05 58 sills, the only variable found to significantly predict immediate post intervention clearance " failures" was the percent of windows replaced out of the total number of windows in a dwelling unit. The higher the percentage of windows replaced, the lower the clearance " failures." On window troughs, the variables found to predict immediate post intervention clearance " failures" were number of items of exterior building deterioration ( increasing number would yield more clearance " failures") and percent of windows replaced ( increasing percent would yield fewer clearance " failures").

3. Predicting Immediate Post Intervention Visual Assessment " Failures"

A logistic model with backward elimination was also employed to predict whether dwelling units would have visual assessment " failures," again using the same set of possible predictors employed for predicting dust lead loading at immediate post intervention and dust lead loading " failures." The only variable found to significantly influence visual assessment " failure" was the number of items of exterior building deterioration; increasing numbers would yield more visual assessment " failures."

IX. ONE YEAR POST INTERVENTION ( PHASE III) RESULTS On the average, one year post intervention visits occurred 55 weeks after the immediate postintervention sampling visit, with a minimum of 40 weeks and a maximum of 74 weeks between the two visits. Of the 121 units that had the prescribed lead hazard reduction treatment interventions and a full immediate post intervention assessment, a total of 73 units ( 36 LHR and 37 LHR+ W) completed one year post intervention dust lead sampling and a full one year postintervention visual assessment. The relationship between various one year post intervention factors and the assigned treatment group ( i. e., LHR versus LHR+ W units) was examined using various statistical tests.

A. Physical Characteristics and Baseline Condition of Enrolled Units Having One Year Post Intervention Data Section V. A and Appendices C and D contain detailed discussions and lists of the physical characteristics and baseline conditions for the 177 units that underwent complete preintervention visual assessments, including those having one year post intervention data. Because these variables may have influenced one year post intervention results, and because these variables may be different for the smaller one year post intervention dataset of 73 units, this section summarizes baseline characteristics and conditions, including pre intervention dust lead loadings, for the 73 units for which one year post intervention data were collected.

1. Baseline Physical Characteristics for Enrolled Units Having One Year Post Intervention Data The majority ( 81%) of the 73 one year post intervention units were single family rowhouses, two were single detached residences, and the remaining units were present in multifamily buildings ( two in duplexes, one in a two flat, two in a triplex, and seven in building with more 11/ 23/ 05 59 than 4 units). This grouping is not significantly different from that of the larger dataset based on Fisher's exact test ( p= 0.39 and 0.14 in LHR and LHR+ W units, respectively).

Eighty five percent of the one year post intervention units were constructed 70 or more years ago, with the largest percentage ( 42%) built between 1920 and 1929. Controlling for treatment group, this grouping is not significantly different from that of the larger dataset discussed in Section VII. A based on Mantel Haenszel's mean score statistic ( p= 0.28). Other baseline dwelling unit characteristics are summarized in Table 28.

Table 28: Dwelling Unit Baseline Characteristics for One Year Post Intervention Units Dwelling Unit Characteristic ( 36 LHR, 37 LHR+ W Units) Mean ( std. deviat.) LHR Units Mean ( std. deviat.) LHR+ W Units Mean ( std. deviat.) All Units Estimated market value of dwelling unit ( mean rounded to nearest $ 100) $ 23,400 ( 12,400) $ 24,000 ( 14,800) $ 23,700 ( 13,600) # of rooms in dwelling unit 7 ( 1) 7 ( 1) 7 ( 1) # of bedrooms in dwelling unit 3 ( 1) 3 ( 1) 3 ( 1) # of windows in dwelling unit 10 ( 3) 11 ( 4) 10 ( 3) # of unpainted windows in dwelling unit ( e. g., vinyl, aluminum) 2 ( 4) 1 ( 2) 1 ( 3)

Approximate square feet of living space 1,100 ( 280) 1,100 ( 330) 1,100 ( 305)

2. Baseline Exterior Building and Interior Unit Conditions for One Year Post Intervention Units Baseline exterior building conditions for the 73 one year post intervention units are summarized in Table 29 on page 60, which lists the seven items checked by the LAAP inspectors on their initial visit to each unit. Table 30 on page 60 lists the number of observed items of exterior building deterioration in the 73 one year post intervention units. In general, there were minimal observed differences in exterior deterioration between the LHR and LHR+ W units, with none of the types of exterior building deteriorations being significantly associated with assigned treatment group based on Fisher's exact tests.

Based on Cochran Mantel Haenszel statistical testing, the number of observed items of exterior building deterioration was also not significantly associated with assigned treatment group ( p= 0.37; see Table 30 on page 60). Controlling for treatment group, the 73 unit one year postintervention dataset tended to have more exterior deteriorations than the larger dataset discussed in Section VII. A. 2 based Mantel Haenszel mean score statistic ( p< 0.001). 11/ 23/ 05 60 Table 29: Baseline Exterior Building Deterioration Summary for One Year Post Intervention Units Types of Exterior Building Deteriorationa ( 36 LHR units, 37 LHR+ W units) LHR # Units (% Units) LHR+ W # Units (% Units) All Units # Units (% Units)

Roofs, gutters, downspouts   missing, broken, holes, cracks 3 ( 8%) 7 ( 19%) 10 ( 14%)

Chimney   cracked, bricks loose or missing, unstable, out of plumb 1 ( 3%) 1 ( 3%) 2 ( 3%)

Walls and siding   large cracks or holes, boards or shingles broken or missing 4 ( 11%) 6 ( 16%) 10 ( 14%)

Windows and doors     two windows or doors broken, missing, boarded up 7 ( 19%) 9 ( 24%) 16 ( 22%)

Porch or steps   major elements broken, missing, out of plumb 2 ( 6%) 4 ( 11%) 6 ( 8%)

Foundation   major visible cracks, missing materials, unsound 0 1 ( 3%) 1 ( 1%)

Evidence of exterior ground contaminated with paint chips 7 ( 19%) 10 ( 27%) 17 ( 23%)

Source: Form 02 a Based on Fisher's Exact test, none of the 7 types of exterior building deterioration were significantly associated with assigned treatment group ( p varied from 0.31 to 1).

Table 30: Number of Baseline Exterior Building Deterioration Items for One Year Post Intervention Units # Items of Exterior Deterioration per Buildinga ( 36 LHR units, 37 LHR+ W units) LHR # Units (% Units) LHR+ W # Units (% Units) All Units # Units (% Units) " 0" items of exterior deterioration 19 ( 53%) 15 ( 40%) 34 ( 47%) " 1" item of exterior deterioration 12 ( 33%) 13 ( 35%) 25 ( 34%) " 2" items of exterior deterioration 3 ( 8%) 5 ( 14%) 8 ( 11%) " 3" items of exterior deterioration 2 ( 6%) 1 ( 3%) 3 ( 4%) " 4" items of exterior deterioration 0 3 ( 8%) 3 ( 4%) Source: Form 02 aBased on Cochran Mantel Haenszel test, the number of exterior deterioration items was not significantly associated with assigned treatment group ( p= 0.37).

Baseline interior dwelling unit conditions for the 73 one year post intervention units are summarized in Table 31 on page 61, which lists the five items checked by LAAP inspectors during their initial visit to each unit, and in Table 32 on page 61, which lists the number of observed items of interior unit deterioration in the 73 units. LHR+ W units had higher percentages of interior deterioration than LHR units for three of the five items. Most notably, LHR+ W units were more likely than LHR units to have walls, ceilings, doors, and trim in need of repair, replacement or repainting. This type of interior deterioration was significantly associated with assigned treatment group based on Fisher's exact testing ( p= 0.0559). Controlling for treatment group, the one year post intervention dataset did not significantly differ 11/ 23/ 05 61 from the dataset discussed in Section VII. A. 2 in terms of the number of interior deteriorations based on a Mantel Haenszel mean score statistic ( p= 0.28).

Table 31: Summary of Baseline Interior Dwelling Unit Deterioration for One Year Post Intervention Units Type of Interior Dwelling Unit Deterioration ( 36 LHR units, 37 LHR+ W units) LHR # Units (% Units) LHR+ W # Units (% Units) All Units # Units (% Units) Walls, ceiling, doors and trim   cracks, need for repair, replace or major repaintinga 10 ( 28%) 19 ( 51%) 29 ( 40%)

Floors   loose, missing or cracked, finish worn, deteriorated carpeting 21 ( 58%) 25 ( 68%) 46 ( 63%)

Heating/ cooling and plumbing   need for extensive repair 5 ( 14%) 5 ( 14%) 10 ( 14%)

Interior damage due to roof leak   need for extensive repair 5 ( 14%) 5 ( 14%) 10 ( 14%)

Rooms with > 2 ft2 of paint deterioration on walls, woodwork, doors, windows, etc. 27 ( 75%) 32 ( 89%) 59 ( 81%)

Source: Form 02 aBased on Chi square testing, deterioration of walls, ceilings, doors and trim was significantly associated with assigned treatment group ( p= 0.0559). None of the other four types of interior deterioration were associated with treatment group ( p varied from 0.47 to 1).

The total number of baseline interior unit deterioration items for the one year post intervention units was not significantly associated with assigned treatment group ( p= 0.5956; see Table 32).

Table 32: Number of Baseline Interior Dwelling Unit Deterioration Items for One Year Post Intervention Units Number of Items of Interior Deterioration per Dwelling Unit ( 36 LHR Units, 37 LHR+ W Units) a LHR # Units (% Units) LHR+ W # Units (% Units) All Units # Units (% Units)

" 0" items of interior deterioration 11 ( 31%) 7 ( 19%) 18 ( 25%) " 1" item of interior deterioration 13 ( 36%) 13 ( 35%) 26 ( 35%) " 2" items of interior deterioration 8 ( 22%) 10 ( 27%) 18 ( 25%) " 3" items of interior deterioration 4 ( 11%) 7 ( 19%) 11 ( 15%) Source: Form 02 aTotal number of items of interior deterioration was not significantly associated with assigned treatment group based on Cochran Mantel Haenszel testing ( p= 0.5956).

3. Pre Intervention Dust Lead Loadings for the 73 One Year Post Intervention Units Pre Intervention Composite Dust Lead Loadings. Composite dust samples were collected from bare floors, interior window sills, window troughs and when necessary from carpeted floors in all one year post intervention LHR and LHR+ W units. Because very few one year postintervention units had carpeted floors, sample results for carpeted floors were excluded from this report. For the three surface types, the median pre intervention dust lead loadings in the LHR+ W units were greater than those in the LHR units ( Table 33 on page 62). Pre intervention 11/ 23/ 05 62 composite dust lead loadings were marginally significantly associated with assigned treatment group for bare floors and window troughs ( p= 0.0676 and 0.0547, respectively) but not for window sills ( p= 0.1109). Controlling for treatment group, the 73 unit one year post intervention dataset was not significantly different from the larger pre intervention dataset ( see Section VII. B. 1) in terms of pre intervention composite dust lead loadings on bare floors, sills and troughs ( p= 0.16, 0.57 and 0.40, respectively).

Table 33: Pre Intervention Composite Sample Dust Lead Loading for One Year Post Intervention Units Surface Type LHR Dust Lead Loading ( µ g/ ft2) 5th Percentile 25th Percentile Median 75th Percentile 95th Percentile Geometric Mean 95% Confid. Limits LHR+ W Dust Lead Loading ( µ g/ ft2) 5th Percentile 25th Percentile Median 75th Percentile 95th Percentile Geometric Mean 95% Confid. Limits Bare floorsa, b ( 34 LHR units, 34 LHR+ W units) 30 64 120 639 36,400 251 ( 127; 498) 38 128 454 1,635 16,800 495 ( 263; 933) Interior window sillsa, b ( 35 LHR units, 37 LHR+ W units) 31 384 1,739 7,520 32,366 1,283 ( 592; 2,780) 287 979 2,930 9,920 234,305 3,850 ( 1,982, 7,480) Window troughsa, b ( 35 LHR units, 37 LHR+ W units) 67 2,050 10,219 34,648 132,166 7,070 ( 3,318; 15,065) 1,774 4,610 12,524 128,571 447,429 21,888 ( 11,578; 41,378) Source: Form 04A, Phase III aApproximately 95% of bare floor composites, interior window sill composites, and window trough composites were comprised of 4 sub samples; the rest were comprised of either 2 or 3 sub samples. b Based on a Kruskal Wallis test, median pre intervention composite dust lead loadings were marginally significantly associated with assigned treatment group for bare floors and window troughs ( p= 0.0676 and 0.0547, respectively) but not for window sills ( p= 0.1109).

Pre Intervention Single Surface Dust Lead Loadings. Single surface dust samples were collected from bare floors, interior window sills, window troughs and, when necessary, from carpeted floors in all one year post intervention LHR and LHR+ W units. Because very few one 11/ 23/ 05 63 year post intervention units had carpeted floors, sample results for carpeted floors were excluded from this report. As previously discussed, single surface samples were collected in a subset of LHR units. However, due to budget constraints, LAAP ceased collecting such samples in LHR units during one year and two years post intervention, but continued to collect single surface samples in LHR+ W units. Therefore, pre intervention single surface results are summarized only for LHR+ W units ( see Table 34).

Table 34: Pre Intervention Single Surface Sample Dust Lead Loadings for One Year Post Intervention Unitsa Surface Type LHR+ W Dust Lead Loading ( µ g/ ft2) 5th Percentile 25th Percentile Median 75th Percentile 95th Percentile Geometric Mean 95% Confid. Limits Baltimore HUD Unitsb ( µ g/ ft2) 5th Percentile 25th Percentile Median 75th Percentile 95th Percentile Geometric Mean 95% Confid. Limits Bare floorsb ( 36 LHR+ W units; 249 Balt HUD units) 52 154 440 2,296 72,761 646 ( 319; 1,305) 36 114 289 629 1,928 270 ( 231; 317) Interior window sillsb ( 36 LHR+ W units) 122 772 1,987 8,797 363,045 3,498 ( 1,605; 7,622) 254 909 2,732 7,142 30,498 2,670 ( 2,222; 3,209) Window troughsb ( 36 LHR+ W units) 381 2,039 17,083 131,591 547,652 17,107 ( 8,079; 36,222) 136 1,300 3,909 14,263 75,911 4,114 ( 3,253; 5,204) Source: Form 04B aOnly two LHR units had Phase III single surface samples collected; therefore, no pre intervention single surface results are presented for LHR units. b Baltimore HUD unit data are from Baltimore Round One housing units enrolled in the National Evaluation of HUD's Lead Hazard Control Grant Program. Baltimore HUD unit data are for units that were vacant at Phase I. Both interior floor and entry floor data are included. cBased on Wilcoxon rank sum testing, pre intervention median single surface dust lead loadings for floors were marginally significant ( p= 0.045), sills were not significantly different( p= 0.969) and troughs were significantly different ( p= 0.001) from those for Baltimore HUD units. 11/ 23/ 05 64 Median pre intervention single surface dust lead loadings on bare floors and troughs in LHR+ W units were greater than those in Baltimore HUD units, while those on sills in LHR+ W units were less than those in Baltimore HUD units. Looking at other percentile values, it generally appears that LHR+ W units had greater baseline dust lead loadings than did Baltimore HUD units, implying that LHR+ W units were in worse condition before treatment. However, Wilcoxon rank sum testing indicates that pre intervention median single surface dust lead loadings for floors were marginally significantly different ( p value= 0.045), those for sills were not significantly different ( p value= 0.969), and those for troughs were significantly different ( p value= 0.001) from those in Baltimore HUD units.

B. One Year Post Intervention Composite and Single Surface Dust Sampling Results A complete listing of one year post intervention composite and single surface dust sample results is provided in Appendices E and F, respectively.

1. Summary of One Year Post Intervention Composite Dust Sampling Results During one year post intervention, composite dust samples were taken from bare floors, interior window sills, window troughs and, when necessary, carpeted floors in all enrolled LHR and LHR+ W units. Because very few one year post intervention units had carpeted floors, sample results for carpeted floors were excluded from this report. A Wilcoxon rank sum test was used to test the equality of the median dust lead loadings for the assigned treatment group ( i. e., LHR versus LHR+ W units). Differences in median one year post intervention dust lead loadings between the two groups had to be accounted for before the continued effectiveness of the prescribed lead hazard reduction treatments could be fully evaluated.

In both LHR and LHR+ W units, one year post intervention median composite dust lead loadings for bare floors were substantially less than the floor clearance standard of 100 µ g/ ft2; however, 11% of LHR units and 6% of LHR+ W units had at least one composite bare floor result above 100 µ g/ ft2. One year post intervention median window sill composite results for both treatment groups were less than 500 µ g/ ft2; however, 47% of LHR units and 11% of LHR+ W units had composite sill results above this level. Median loadings for LHR units were three times higher than those for LHR+ W units. For troughs, one year post intervention median composite dust lead loadings in LHR+ W units were also less than the clearance standard of 800 µ g/ ft2; however, the LHR median trough result of 1,074 µ g/ ft2 exceeded this clearance standard. Over half ( 58%) of LHR units but only 16% of LHR+ W units had one year post intervention trough composite results above 800 µ g/ ft2. For the window surface types, the median one year post intervention composite dust lead loadings in the LHR units substantially exceeded those for the LHR+ W units. Based on Wilcoxon rank sum tests, these differences were significant for sills and troughs 11/ 23/ 05 65 ( p= 0.0052 and 0.0025, respectively) but not for bare floors ( p= 1.0; see Table 35 and Figure 10 on page 66).

Table 35: One Year Post Intervention Composite Sample Dust Lead Loadings Surface Type LHR Dust Lead Loading ( µ g/ ft2) 5th Percentile 25th Percentile Median 75th Percentile 95th Percentile Geometric Mean 95% Confid. Limits LHR+ W Dust Lead Loading ( µ g/ ft2) 5th Percentile 25th Percentile Median 75th Percentile 95th Percentile Geometric Mean 95% Confid. Limits Bare floorsa, b ( 35 LHR units, 33 LHR+ W units) 2 7 22 75 203 23 ( 14; 38) 2 11 20 38 250 23 ( 15; 36) Interior window sillsa, b ( 36 LHR units, 37 LHR+ W units) 1 85 449 1,045 8,466 252 ( 99; 640) 9 29 121 239 1,666 90 ( 56; 145) Window troughsa, b ( 35 LHR units, 37 LHR+ W units) 2 170 1,074 11,550 56,707 1,061 ( 403; 2,795) 22 118 247 510 1,731 242 ( 160; 367) Source: Form 04A, Phase III aApproximately 85% of bare floor composites, interior window sill composites, and window trough composites were comprised of 4 sub samples; the rest were comprised of either 2 or 3 sub samples. b Based on Wilcoxon rank sum tests, median one year post intervention dust lead loadings for sills and troughs were significantly associated with assigned treatment group ( p= 0.0052 and 0.0025, respectively) but not for bare floors ( p= 1.0). 11/ 23/ 05 66 Figure 10: Pre and One Year Post Intervention Composite Sample Dust Lead Loading Box Plot 1 10 100 1000 10000 100000 1000000 Pre Int.

1 Yr Post Int.

Pre Int.

1 Yr Post Int.

Pre Int.

1 Yr Post Int.

Pre Int.

1 Yr Post Int.

Pre Int.

1 Yr Post Int.

Pre Int.

1 Yr Post Int.

LHR LHR+ W LHR LHR+ W LHR LHR+ W Bare Floors Window Sills Window Troughs Dust Lead Loading ( ug/ ft^ 2)

Note: Bottom whisker= 5th percentile; top whisker= 95th percentile; box= 25th & 75th percentile; circle= median; triangle = geometric mean.

2. Change in Composite Results from Pre to One Year Post Intervention Given that all visual assessment " failures" found at immediate post intervention were corrected upon discovery and that all immediate post intervention samples were collected prior to these corrections, it is not appropriate to compare immediate post intervention dust lead loadings with those measured at one year post intervention. However, comparison of one year postintervention results with pre intervention results aids in evaluating treatment effectiveness one year after intervention. 11/ 23/ 05 67 Large median percent decreases and median µ g/ ft2 decreases were observed when measuring the change from pre to one year post intervention for composite samples taken from bare floors, window sills and window troughs ( see Tables 36 and 37, and Figure 10). Results indicate that at one year post intervention, composite dust lead loadings on bare floors, sills and troughs in both treatment groups generally remained well below pre intervention levels in both treatment groups. Based on Wilcoxon rank sum testing, the association between the median percent reduction in median composite dust lead loadings and the assigned treatment group was significant for window sills ( p< 0.0001) and troughs ( p= 0.0001) but not for bare floors ( p= 0.2270).

Table 36: Percent Reduction in Pre to One Year Post Intervention Composite Dust Lead Loadings Surface Type and Statistic Composite Dust Samples LHR Units Pre to 1 Yr Post Intervention Percent Change LHR+ W Units Pre to 1 Yr Post Intervention Percent Change Bare floors ( 34 LHR, 32 LHR+ W) a: 25th Percentile Percent Reduction Median Percent Reduction 75th Percentile Percent Reduction 53 82 95 76 94 98 Interior window sills ( 35 LHR, 37 LHR+ Wa 25th Percentile Percent Reduction Median Percent Reduction 75th Percentile Percent Reduction  45 ( increase) 82 96 94 97 99 Window troughs ( 34 LHR, 37 LHR+ W) a 25th Percentile Percent Reduction Median Percent Reduction 75th Percentile Percent Reduction 4 89 96 93 98 > 99 Source: Form 04A aBased on Wilcoxon rank sum tests, although changes in median bare floor dust lead loadings were not significantly associated with assigned treatment group ( p= 0.2246), changes in median sill and trough loadings were ( p< 0.0001 and p= 0.0001, respectively).

Based on Wilcoxon rank sum testing, the association between the absolute reduction in median composite dust lead loadings and the assigned treatment group was significant for window sills ( p= 0.0185) and troughs ( p= 0.0047) but not for bare floors ( p= 0.1600) ( see Table 37). 11/ 23/ 05 68 Table 37: Micrograms Per Square Foot Reduction in Pre to One Year Post Intervention Composite Dust Lead Loadings Surface Type and Statistic Composite Dust Samples LHR Units Pre to 1 Yr Post Intervention µ g/ ft2 Reduction LHR+ W Units Pre to 1 Yr Post Intervention µ g/ ft2 Reduction Bare floors ( 34 LHR, 32 LHR+ W) a: 25th Percentile µ g/ ft2 Reduction Median µ g/ ft2 Reduction 75th Percentile µ g/ ft2 Reduction 35 87 486 71 335 804 Interior window sills ( 35 LHR, 37 LHR+ W) a: 25th Percentile µ g/ ft2 Reduction Median µ g/ ft2 Reduction 75th Percentile µ g/ ft2 Reduction  25 ( increase) 713 6,458 693 2,803 9,771 Window troughs ( 34 LHR, 37 LHR+ W) a: 25th Percentile µ g/ ft2 Reduction Median µ g/ ft2 Reduction 75th Percentile µ g/ ft2 Reduction 2 4,507 23,385 4,356 12,014 128,550 Source: Form 04A aBased on Wilcoxon rank sum tests, although changes in median bare floor dust lead loadings were not significantly associated with assigned treatment group ( p= 0.1600), changes in sill and trough loadings were ( p= 0.0185 and p= 0.0047, respectively).

3. Units Having an Increase in Composite Dust Lead Loadings from Pre to One Year Post Intervention Despite the significant median decreases in composite dust lead loadings between pre and oneyear post intervention, data in Table 38 show that some units experienced increases in dust lead loadings between these two phases. Indeed, the findings show that approximately a quarter of LHR units had an increase in composite dust lead loadings on sills and troughs during this time period. The percentages of LHR+ W units that underwent an increase were lower than those of LHR units.

Table 38: Number and Percent of Units Having an Increase in Composite Dust Lead Loadings from Pre to One Year Post Intervention Surface Type and Sample Type LHR LHR+ W Bare Floors: 3/ 34 ( 9%) 1/ 32 ( 3%)

Interior window sills: 10/ 35 ( 28%) 1/ 37 ( 3%)

Window Troughs: 8/ 34 ( 24%) 0/ 37 ( 0%) 11/ 23/ 05 69 4. Summary of One Year Post Intervention Single Surface Results As discussed in Section II. E, single surface samples were collected in a subset of LHR units. However, due to budget constraints, LAAP ceased collecting such samples in LHR units during one year and two years post intervention but continued to collect them in LHR+ W units. Samples were collected in the same locations of LHR+ W units that were sampled during the first two study phases ( see Table 39 on page 70 and Figure 11 on page 71). There were too few carpeted floor samples to allow full characterization of this surface type. The one year postintervention single surface dust sample results for LHR+ W units were compared with one year post intervention single surface dust data obtained from Baltimore City housing units enrolled in the National Evaluation of HUD's Lead Hazard Control Grant program. These units underwent lead reduction control interventions that were generally similar to those received by the LHR+ W units during this study.

Median single surface one year post intervention dust lead loading results for bare floors and window troughs in LHR+ W units were less than those in Baltimore HUD Evaluation units, while the median single surface dust lead loading for sills in LHR+ W units was slightly higher than that of Baltimore HUD units. Based on Wilcoxon rank sum tests, these differences were significant for bare floors ( p< 0.0001) and troughs ( p= 0.0017) but not for sills ( p= 0.545). These results are somewhat surprising given that the HUD Round I units generally underwent similar lead hazard control treatments as the LHR+ W units and given that the LHR+ W units generally had higher pre intervention dust lead loadings than the Baltimore Round I units.

5. Change in Single Surface Results from Pre to One Year Post Intervention Similar to the composite dust lead loading results, substantial median percent decreases and median µ g/ ft2 decreases in single surface dust lead loadings were observed for floors, sills and window troughs between pre and one year post intervention ( see Tables 40 and 41 on pages 72 and 73). Based on Wilcoxon rank sum tests, median percent reductions for bare floors and troughs in LHR+ W units were significantly different from those for Baltimore Round I HUD Evaluation units ( p< 0.0001 for both surface types) but were not significantly different for window sills ( p= 0.813). Again, these results are surprising given that LHR+ W units appeared to have larger pre intervention dust lead loadings and were treated in a similar manner to HUD Round I units. 11/ 23/ 05 70 Table 39: One Year Post Intervention Single Surface Sample Dust Lead Loadingsa Surface Type LHR+ W Dust Lead Loading ( µ g/ ft2) 5th Percentile 25th Percentile Median 75th Percentile 95th Percentile Geometric Mean 95% Confid. Limits Baltimore HUD Unitsb ( µ g/ ft2) 5th Percentile 25th Percentile Median 75th Percentile 95th Percentile Geometric Mean 95% Confid. Limits Bare floorsc ( 36 LHR+ W units) ( 249 Balt Rd I units) 4 11 20 37 141 20 ( 15; 28) 5 21 44 90 319 42 ( 36; 48) Interior window sillsc ( 36 LHR+ W units) ( 237 Balt Rd I) 10 23 64 152 3,628 69 ( 41; 118) 4 18 58 139 505 50 ( 42; 61) Window troughsc ( 36 LHR+ W units) ( 242 Balt Rd I) 18 78 211 391 1,058 185 ( 122; 282) 51 143 421 917 2,233 376 ( 321; 441) Source: Form 04B aOnly two LHR units had Phase III single surface samples collected; therefore, no comparison with pre intervention single surface results is possible. bBaltimore HUD unit data are from Baltimore Round One housing units enrolled in the National Evaluation of HUD's Lead Hazard Control Grant Program. Units were vacant at pre intervention. For floors, Baltimore HUD unit data include both interior floor and entry floor data. cBased on Wilcoxon rank sum tests, LHR+ W median dust lead loadings for floors and troughs were significantly different from those of Baltimore Round I units ( p< 0.0001 for floors and 0.0017 for troughs) but not for sills ( p= 0.545). 11/ 23/ 05 71 Figure 11: Pre and One Year Post Intervention Single Surface Sample Dust Lead Loading Box Plot 1 10 100 1000 10000 100000 1000000 Pre Int.

1 Yr Post Int.

Pre Int.

1 Yr Post Int.

Pre Int.

1 Yr Post Int.

Pre Int.

1 Yr Post Int.

Pre Int.

1 Yr Post Int.

Pre Int.

1 Yr Post Int.

LHR+ W Balt. HUD LHR+ W Balt. HUD LHR+ W Balt. HUD Bare Floors Window Sills Window Troughs Dust Lead Loading ( ug/ ft^ 2)

Note: Bottom whisker= 5th percentile; top whisker= 95th percentile; box= 25th & 75th percentile; circle= median; triangle = geometric mean. 11/ 23/ 05 72 Table 40: Percent Reduction in Pre to One Year Post Intervention Single Surface Dust Lead Loadingsa Surface Type and Statistic Single Surface Dust Samples LHR+ W Units Pre to 1 Yr Post Intervention Percent Reduction Baltimore HUD Unitsa Pre to 1 Yr Post Intervention Percent Reduction Bare floors ( 36 LHR+ W; 249 Balt HUD) b: 25th Percentile Percent Reduction Median Percent Reduction 75th Percentile Percent Reduction 88% 96% 99% 63% 84% 94%

Interior window sills ( 36 LHR+ W; 237 Balt HUD) b: 25th Percentile Percent Reduction Median Percent Reduction 75th Percentile Percent Reduction 75% 97% > 99% 93% 98% 99%

Window troughs ( 36 LHR+ W; 242 Balt HUD) b: 25th Percentile Percent Reduction Median Percent Reduction 75th Percentile Percent Reduction 93% 99% > 99% 60% 90% 98%

Source: Form 04B aOnly two LHR units had Phase III single surface samples collected; therefore, no comparison with pre intervention single surface results is possible. bBaltimore HUD unit data are Round I data from the National Evaluation of HUD's Lead Based Paint Grant Program and were compiled using pre intervention and one year post intervention data and were from units that were vacant at pre intervention. For floors, Baltimore HUD unit data include both interior floor and entry floor data. cBased on Wilcoxon rank sum tests, LHR+ W units had significantly larger median percent decreases in single surface dust lead loadings for bare floors ( p< 0.0001) and troughs ( p< 0.0001) than did Baltimore Round I units; however, median percent decreases in sill loadings were not significantly different ( p= 0.813). 11/ 23/ 05 73 Table 41: Micrograms Per Square Foot Reductions in Pre to One Year Post Intervention Single Surface Dust Lead Loadingsa Surface Type and Statistic Single Surface Dust Samples LHR+ W Units Pre to 1 Yr Post Intervention µ g/ ft2 Reduction Baltimore HUD Units Pre to 1 Yr Post Intervention µ g/ ft2 Reductionb Bare floors ( 36 LHR+ W; 249 Balt HUD): 25th Percentile µ g/ ft2 Reduction Median µ g/ ft2 Reduction 75th Percentile µ g/ ft2 Reduction 148 µ g/ ft2 420 µ g/ ft2 2,396 µ g/ ft2 57 µ g/ ft2 220 µ g/ ft2 557 µ g/ ft2 Interior window sills ( 36 LHR+ W; 237 Balt HUD): 25th Percentile µ g/ ft2 Reduction Median µ g/ ft2 Reduction 75th Percentile µ g/ ft2 Reduction 540 µ g/ ft2 1,875 µ g/ ft2 10,322 µ g/ ft2 860 µ g/ ft2 2,617 µ g/ ft2 7,114 µ g/ ft2 Window troughs ( 36 LHR+ W; 242 Balt HUD)): 25th Percentile µ g/ ft2 Reduction Median µ g/ ft2 Reduction 75th Percentile µ g/ ft2 Reduction 1,758 µ g/ ft2 16,338 µ g/ ft2 135,512 µ g/ ft2 800 µ g/ ft2 3,308 µ g/ ft2 13,283 µ g/ ft2 Source: Form 04B aOnly two LHR units had Phase III single surface samples collected; therefore, no comparison with pre intervention single surface results is possible. bBaltimore HUD unit data are Round I data from the National Evaluation of HUD's Lead Hazard Control Grant Program and were compiled using initial and Phase 4 data ( one year post intervention) for units that were vacant at pre intervention. For floors, Baltimore HUD unit data include both interior floor and entry floor data.

6. Units Having an Increase in Single Surface Dust Lead Loadings from Pre to One Year Post Intervention Despite the substantial median decreases in dust lead loadings between pre and one year postintervention data in Table 42 show that a few units experienced increases in single surface dust lead loadings between these two phases. The percentages of LHR+ W units that underwent an increase on floors and troughs were lower than those of Baltimore HUD units, while the sill percentage was slightly higher than that of Baltimore HUD units.

Table 42: Number and Percent of Units Having an Increase in Single Surface Dust Lead Loadings from Pre to One Year Post Intervention Surface Type and Sample Type LHR+ W Baltimore HUD Units Bare Floors: 1/ 36 ( 3%) 25/ 249 ( 10%)

Interior window sills: 3/ 36 ( 8%) 2/ 237 ( 1%)

Window Troughs: 2/ 36 ( 6%) 28/ 242 ( 12%) 11/ 23/ 05 74 7. Comparison of One Year Post Intervention Results with Clearance Standards/ Guidance Under the risk reduction treatment option of EA 6 8, enrolled LHR and LHR+ W units were required only to pass a visual inspection performed by an independent visual inspector immediately after intervention was complete. Collection of dust samples and comparison of such results to clearance standards were not required during any phase. However, this study considered clearance dust standards set by Maryland and by HUD/ EPA to assess the extent to which prescribed treatments continued to produce dust results that were sufficient for safe occupancy of treated units one year after treatments were complete. This comparison to clearance standards is not required by EA 6 8 and was performed in this study for research purposes only. Again, only LHR+ W units are presented here because one year post intervention single surface data were not available for the vast majority of LHR units.

One year after interventions were completed, less than 20% of LHR+ W units had single surface dust lead loadings that exceeded clearance standards for any surface type ( see Table 43). At oneyear post intervention, Baltimore HUD units had a higher percentage of bare floors and window troughs that exceeded HUD clearance standards of 100 and 500 µ g/ ft2, respectively. Based on Chi square testing, there is a significant difference between the clearance exceedance rate for LHR+ W units versus Baltimore HUD units ( p< 0.0001 for bare floors, p= 0.016 for troughs). LHR+ W units had a higher percentage of units with window sills above 500 µ g/ ft2; however, there was only a marginally significant difference based on a Fisher's Exact Test ( p= 0.096). This is surprising given the fact that LHR+ W units generally had larger pre intervention dust lead loadings and treatments that were similar to those of Baltimore HUD round I units. Visual assessment " failures" reported at immediate post intervention that were subsequently repaired may have contributed to the relatively lower rates for LHR+ W units.

Table 43: Percentage of LHR+ W Units with One Year Post Intervention Single Surface Dust Lead Loadings Exceeding Clearance Standardsa Percent of Units within Specified Category Surface Type: Bare Floors Interior Window Sills Window Troughs Std/ Guidance:

100 µ g/ ft2

200 µ g/ ft2

500 µ g/ ft2

800 µ g/ ft2 LHR+ W Units ( 36 units) 5 ( 14%) 4 ( 11%) 6 ( 17%) 5 ( 14%)

Baltimore HUD Unitsb ( 249 units) 143 ( 57%) NA 25 ( 11%) 85 ( 35%)

aOnly two LHR units had Phase III single surface samples collected; therefore, no comparison with clearance standards/ guidance is possible. bBaltimore HUD unit data are Round I data from the National Evaluation of HUD's Lead Hazard Control Grant Program and were compiled using initial and Phase 4 data ( one year post intervention) for units that were vacant at pre intervention. For floors, Baltimore HUD unit data include both interior floor and entry floor data.

C. Results of One Year Post Intervention Visual Assessment At one year post intervention, LAAP inspectors performed another visual assessment to evaluate the continued effectiveness of treatments one year after intervention. A complete listing of oneyear post intervention visual assessment " failures" is provided in Appendix G. Table 44 presents 11/ 23/ 05 75 the distribution of one year post intervention " failures" per unit. There were no units having more than five " failures." LAAP inspectors found that all 36 LHR units and 34 of the 37 ( 92%) LHR+ W units had at least one visual assessment " failure" one year after interventions had been completed. This equates to an overall one year post intervention visual assessment " failure" rate of 96% for the 73 one year post intervention units. Landlords were informed of these " failures" and were provided with recommendations to fix the problems.

Overall, the likelihood of LHR units having one or more one year post intervention " failures" was almost the same as that of the LHR+ W units. However, t tests indicate that the mean number of " failures" per unit for LHR units ( 2.4) was marginally significantly different from and higher than that for LHR+ W units ( 1.9) ( p= 0.0482). If only " failure" types applicable to both treatment groups are considered, LHR units have a slightly lower mean number of one year postintervention " failures" per unit ( 2.2), while the mean for LHR+ W units remains almost the same ( 1.8); these two means are not significantly different from each other based on t tests ( p= 0.1246).

Table 44: Number of One Year Post Intervention Visual Assessment " Failures" Per Unit Number of One Year Post Intervention Visual Assessment " Failures" Per Unita ( 36 LHR units, 37 LHR+ W units) LHR # Units (% Units) LHR+ W # Units (% Units) All Units # Units (% Units)

" 0" 1 yr post int visual assessment " failures" 0 3 ( 8%) 3 ( 4%) " 1" 1 yr post int visual assessment " failure" 8 ( 22%) 13 ( 35%) 21 ( 29%) " 2" 1 yr post int visual assessment " failures" 12 ( 33%) 9 ( 24%) 21 ( 29%) " 3" 1 yr post int visual assessment " failures" 11 ( 31%) 9 ( 24%) 20 ( 27%) " 4" 1 yr post int visual assessment " failures" 3 ( 8%) 3 ( 8%) 6 ( 8%) " 5" 1 yr post int visual assessment " failures" 2 ( 6%) 0 2 ( 3%) Source: Form 05 aThe mean number of " failures" per unit for LHR units ( 2.4) was marginally significantly different from that for LHR+ W units ( 1.9) ( p= 0.0482).

1. Types of One Year Post Intervention " Failures"

The most common visual assessment " failure" at one year post intervention was that not all paint was intact after completion of the lead hazard reduction treatments ( i. e., chipping, flaking and/ or peeling paint remained) ( see Table 45 on page 76), with over 90% of all units ( 94% of LHR units and 92% of LHR+ W units) exhibiting this type of " failure." Over 40% of units ( 50% of LHR units and 32% of LHR+ W units) had doors with painted surfaces that continued to rub together or bind. Approximately one third of all units ( 33% of LHR units and 24% of LHR+ W units) had visible paint chips and debris in various locations, and over 25% ( 31% of LHR units and 24% of LHR+ W units) had some kitchen and bathroom floors whose water resistant coverings were not intact. Other types of one year post intervention visual assessment " failures" were much less prevalent. Although LHR units had a higher percentage of units with each of the abovementioned types of " failures," none of the " failure" types was significantly associated with assigned treatment group based on Chi square tests. 11/ 23/ 05 76 Table 45: One Year Post Intervention Visual Assessment " Failures" Type of One Year Post Intervention Visual Assessment " Failures" a ( 36 LHR units, 37 LHR+ W units) LHR # Units (% Units) LHR+ W # Units (% Units) All Units # Units (% Units)

Not all paint intact ( chipping, peeling or flaking paint remains) 34 ( 94%) 34 ( 92%) 68 ( 93%)

Visible structural defect that could cause paint deterioration remains 1 ( 3%) 2 ( 5%) 3 ( 4%)

If sills stripped/ repainted or replaced, not all treatments in place 1 ( 3%) 0 1 ( 1%)

If sills encapsulated with vinyl, metal, etc., not all material is properly attachedb 0 0 0 If troughs capped with vinyl, metal, etc., not all material is properly attachedb 5 ( 14%) NAb 5 ( 7) c For windows, not all top sashes are fixed in place 0 NAb 0 For doors, painted surfaces rub together 18 ( 50%) 12 ( 32%) 30 ( 41%)

Some bare floors are not smooth and cleanable 5 ( 14%) 4 ( 11%) 9 ( 12%)

Not all kitchen and bathroom floors are overlaid with water resistant coverings 11 ( 31%) 9 ( 24%) 20 ( 27%)

Visible paint chips or debris remains 12 ( 33%) 9 ( 24%) 21 ( 29%)

Source: Form 05 aBased on Chi square tests, none of the listed types of visual assessment " failures" were significantly associated with assigned treatment group ( p varied from 0.127 to 0.689). bIn LHR+ W units, these treatments were not necessary by virtue of the installation of new vinyl replacement windows with unpainted top sashes and troughs. cValue is understated due to the inapplicability of this treatment for LHR+ W units.

2. Magnitude of One Year Post Intervention " Failures"

The magnitude of the above " failures" was evaluated by reviewing notes that LAAP inspectors recorded about the observed " failures" by room location and " failure" type, the specific component or surface type that " failed" in a given room, and their estimated measurement of each " failure" in units of linear inches, square inches, linear feet, square feet or " each."

The geometric means of " failures" presented in Table 46 on page 77 were calculated by first summing, within a unit, all reports of a particular " failure" type having the same measurement units ( e. g., square feet), then calculating the geometric mean across dwelling units. These data indicate that problems recorded by LAAP inspectors one year after treatment were easily observed ( see Table 46). For example, LAAP inspectors reported that a geometric mean of 1 ft2 of paint in both LHR and LHR+ W units was not intact at one year post intervention. This type of " failure" was reported 61 times in 23 LHR units and 61 times in 25 LHR+ W units, indicating a widespread occurrence. Painted door surfaces rubbing together was also noted often, reported 22 times in 18 LHR units and 16 times in 12 LHR+ W units. The status of floors at one year 11/ 23/ 05 77 post intervention is also noteworthy, with a geometric mean of 4 ft2 of flooring in both LHR and LHR+ W units being not smooth and cleanable one year after treatments. A geometric mean of 2 ft2 of kitchen and bathroom floors in LHR and LHR+ W units had tile or coverings that were damaged, cracked, or missing. These results are somewhat surprising considering that these types of problems were reportedly corrected during the lead hazard reduction intervention or were corrected when LAAP inspectors discovered such problems during the visual inspection conducted immediately after treatments were completed.

Table 46: Reporting Frequency of Specified Types of One Year Post Intervention Visual Assessment " Failures" LHR LHR+ W " Failure" Type ( 36 LHR, 37 LHR+ W) Unit of Measure # Units with Specified " Failure" Rpt'd Reporting Freq. of " Failure" Type at Ph 2 " Failure" Magnit. ( geom. Mean & 95% Conf Limits) # Units with Specified " Failure" Rpt'd Reporting Freq. of " Failure" Type at Ph 2 " Failure" Magnit. ( geom. mean & 95% Conf Limits) EAa 3 3 1 ( 1, 3) 3 3 2 ( NA) c LF 32 94 2 ( 1, 3) 26 82 2 ( 1, 3) Not all paint intact ( 34 LHR, 34 LHR+ W) SF 23 61 1 ( 0.2, 2) 25 61 1 ( 0.2, 2)

For doors, painted surfaces continued to rub together ( 18 LHR, 12 LHR+ W) EAa 18 22 1 ( 1, 1) 12 16 1 ( 1, 2)

Some bare floors not smooth & cleanable ( 5 LHR, 4 LHR+ W) SF 5 10 4 ( 1, 21) 4 6 4 ( NA) c Not all kitchen & bathroom floors overlaid with water resistant coverings ( 11 LHR, 9 LHR+ W) LF SF 0 11 13 0 2 ( 2, 3) 2 8 3 9 2 ( NA) 2 ( 1, 5)

EAb 4 19 6 ( 4, 10) 3 10 5 ( 2, 13) LF 1 2 8 ( NA) 0 0 NA Visible paint chips or debris remains ( 12 LHR, 9 LHR+ W) SF 7 23 1 ( 0.1, 9) 6 10 1 ( 0.2, 4)

EA= each; LF= linear foot; SF= square foot aFor these " failure" types, " each" denotes window components ( e. g., upper sash, lower sash), door casings, or handrails in need of re painting. LF/ SF values are not available for these occurrences. bFor this " failure" type, " each" usually denotes a window with debris or chips in the well. cNo 95% confidence limits were calculated due to the small number of units having this failure reported. 11/ 23/ 05 78 3. Rooms with One Year Post Intervention " Failures"

In general, three to six rooms per unit ( mean 5 rooms for LHR units and 4 rooms for LHR+ W units) had visual assessment " failures" at one year post intervention ( see Figure 12 on page 74). All LHR units had at least one room with " failures," while 8% of LHR+ W units had no rooms with " failures." Although no LHR+ W units had more than 9 rooms with " failures," 2% of LHR units had 10 or more rooms with " failures."

Figure 12: Percentage of Units Having Specified Number of Rooms Per Unit with One Year Post Intervention Visual Assessment " Failures"

0% 3% 8% 14% 22%

17% 17%

6%

3% 6%

3% 3% 8%

5% 5% 19% 19% 19%

11%

8%

0% 5%

0% 0% 4% 4% 7% 16% 20%

18%

14%

7%

1% 5%

1% 1%

0% 5% 10% 15% 20% 25%

0 1 2 3 4 5 6 7 8 9 10 11 Percentage of Units Having Specified Number of Room with Visual Assessment " Failures" at One Year Post Intervention Percentage of Units LHR Units LHR+ W Units All Units In both LHR and LHR+ W units, paint was not intact in an average of 3 rooms per unit ( see Table 47 on page 79). For other types of " failures" ( e. g., painted doors rubbing, visible paint chips and debris present), a given " failure" was generally reported for 1 room per unit. 11/ 23/ 05 79 Table 47: Mean Number of Rooms Per Unit with Specified One Year Post Intervention Visual Assessment " Failures" by Treatment Groupa Type of Post Intervention Visual Assessment " Failures" ( 36 LHR units, 37 LHR+ W units) LHR Mean # Rooms Per Unit ( 95% Conf. Int.) LHR+ W Mean # Rooms per Unit ( 95% Conf. Int.) Not all paint intact ( chipping, peeling or flaking paint remains) 3.4 ( 2.8, 4.0) 3.2 ( 2.6, 3.8) Visible structural defect that could cause paint deterioration remains 0 ( 0, 0.1) 0.1 ( 0, 0.2) If sills stripped/ repainted or replaced, not all treatments in place 0 ( 0, 0.1) 0 If sills encapsulated with vinyl, metal, etc., not all material is property attached 0 0 If troughs capped with vinyl, metal, etc., not all material is properly attached 0.2 ( 0, 0.3) NAa For windows, not all top sashes are fixed in place 0 NAa For doors, painted surfaces continue to rub together 0.6 ( 0.4, 0.9) 0.4 ( 0.2, 0.6) Some bare floors are not smooth and cleanable 0.3 ( 0.1, 0.5) 0.2 ( 0, 0.3) Not all kitchen and bathroom floors are overlaid with water resistant coverings 0.4 ( 0.2, 0.6) 0.3 ( 0.1, 0.5) Visible paint chips or debris remain 1.2 ( 0.8, 1.6) 0.5 ( 0.3, 0.8) Source: Form 05 aIn LHR+ W units, these treatments were not necessary by virtue of the immediate post intervention installation of new vinyl replacement windows with unpainted top sashes and troughs.

4. Type of Contractor and Number of One Year Post Intervention " Failures"

At immediate post intervention, lead hazard reduction treatments were generally performed by for profit contractors or the property owner/ employees. Only four of the 73 one year postintervention units had been treated by non profit contractors; therefore, these data are excluded from this section's discussion. An average of 5.3 " failures" per unit were observed at one year post intervention in LHR units treated by for profit contractors, and 6.7 in LHR units treated by the property owner/ employees ( see Table 48 on page 80). The mean number of one year postintervention " failures" per unit in LHR+ W units treated by for profit contractors and property owner/ employees was 5.1 and 3.9, respectively. A Poisson regression model was run to predict the number of " failures" per unit at one year post intervention based on assigned treatment group, contractor type ( for profit or property owner/ employees), and their interaction. None of the three variables were significant predictors of the number of visual assessment " failures" per unit. 11/ 23/ 05 80 Table 48: Mean Number of One Year Post Treatment " Failures" per Unit by the Type of Contractora, b Mean Number of " Failures" per Unit Contractor Type LHR Units LHR+ W Units For profit contractor 5.3 5.1 Property owner/ employees 6.7 3.9 Source: Form 05 a Because only four of the 73 had nonprofit contractors performing the work, the number of " failures" is not easily compared against for profit contractors and property owner/ employees work. Therefore, nonprofit contractor data are not presented in this table. bBased on a Poisson regression model, neither the assigned treatment group nor the type of contractor nor the interaction of these two variables were significant predictors of the number of " failures" per unit at Phase III.

D. Follow Up Data Summary for One Year Post Intervention ( Form 06)

Form 06 ( Follow Up Questions) was designed to collect information from the property owner or his/ her designee about any activities that occurred in the unit in the 12 month period after intervention. Only four units reportedly had a change in tenancy. And, in general, few units appear to have had further lead hazard reduction treatments done during the one year postintervention period. During the 12 months prior to LAAP's one year post intervention visit, lead hazard reduction work was reportedly done in six units, four of which had work done at turnover. Costs for this lead hazard reduction work ranged from $ 100 to $ 2,000 ( mean of approximately $ 600), with work done one to eight months before the one year post intervention visit. In two units, tenants reported to the owner that new lead hazards existed; these were not the same two units that had lead hazard reduction work done but no work was completed at turnover. There was one unit for which the owner was notified that a tenant child had a blood lead level between 15 and 24 µ g/ dl. A qualified offer was made for this case. No owner was notified that a tenant child had a blood lead level above 25 µ g/ dl.

E. Statistical Modeling Results for One Year Post Intervention 1. Predicting Dust Lead Loading at One Year Post Intervention A multiple regression model with backward elimination was used with multiple regression to identify factors that are significant predictors of one year post intervention composite dust lead loadings. Composite dust lead loadings were used instead of single surface results because composite data were available for all 73 one year post intervention units. A separate model was run for each surface type ( i. e., bare floors, interior window sills and window troughs). Dust lead loading measurements were log transformed. ( Statistical tables resulting from these models are provided in Appendix I.)

The set of possible predictors considered were:

  Type of building ( e. g., single family or multifamily dwelling);   Year of construction ( e. g., pre 1920 or 1920 1949);   Contractor type ( i. e., for profit, nonprofit, property owner/ employee); 11/ 23/ 05 81   Concurrent work ( i. e., yes or no);   Treatment group ( i. e., LHR or LHR+ W);   Pre intervention composite dust lead loading results for a given surface type ( i. e., bare floors, interior window sills or window troughs);   Number of items of baseline interior dwelling unit deterioration;   Number of items of baseline exterior building deterioration;   Percent of windows replaced out of the total number of windows in a dwelling unit;   Estimated market value of a dwelling unit;   Total lead hazard control cost for a dwelling unit, including window replacement costs, if applicable;   Was work performed during 12 month post intervention period ( yes/ no);   Number of rooms with any visual assessment failures at one year post intervention; and   Interactions of ( 1) the number of interior dwelling unit deterioration items, ( 2) the number of exterior building deterioration items, and ( 3) pre intervention dust lead loadings with each of the following: concurrent work, percent of windows replaced, total lead hazard reduction cost, and assigned treatment group.

The only significant predictor of one year post intervention bare floor dust lead loadings was the percent of rooms with visual assessment " failures" at one year post intervention ( i. e., units with more one year post intervention visual assessment failures were more likely to have higher oneyear post intervention composite floor dust lead loadings). The percentage of variation ( i. e., R2) accounted for in one year post intervention composite dust lead loadings by this variable is 13%. For interior window sills, the variables found to predict one year post intervention dust lead loadings were pre intervention sill dust lead loadings and the assigned treatment group ( R2= 24%) ( i. e., units with higher pre intervention sill dust lead loadings were more likely to have higher one year post intervention dust lead loadings, and LHR units were more likely to have higher sill dust lead loadings than LHR+ W units). The only variable that was predictive of one year postintervention composite dust lead loadings for window troughs was the assigned treatment group ( R2= 10%) ( i. e., LHR units were more likely to have higher one year post intervention composite trough dust lead loadings than LHR+ W units).

2. Predicting One Year Post Intervention Dust Lead Loading Exceedances of Standards Separate logistic regression models with backward elimination were employed to predict whether dwelling units would have one year post intervention dust lead loadings on bare floors, interior window sills and window troughs that exceeded standards of 100 µ g/ ft2, 500 µ g/ ft2, and 800 µ g/ ft2, respectively ( see Appendix I). The same set of possible predictors that were used in predicting dust lead loading at one year post intervention were also employed for this model, except that interactions were not included because they are not appropriate for logistic models.

For bare floors, the only significant predictor of one year post intervention composite results being above a standard of 100 µ g/ ft2 was the year of construction, with older units more likely to yield one year post intervention floor results above 100 µ g/ ft2. For window sills, variables found to significantly predict one year post intervention composite dust lead loadings above a standard of 500 µ g/ ft2 were pre intervention window sill dust lead loadings and assigned treatment group, 11/ 23/ 05 82 with units having higher pre intervention composite sill results more likely to have one year post intervention sill results above 500 µ g/ ft2, and LHR units more likely to have one year postintervention sill results above 500 µ g/ ft2 than LHR+ W units. For window troughs, the only predictor of one year post intervention composite dust lead loadings for window troughs was the assigned treatment group ( R2= 10%), with LHR+ W units less likely to have one year postintervention composite trough results above a standard of 800 µ g/ ft2.

3. Predicting One Year Post Intervention Visual Assessment " Failures"

A Poisson regression model with backward elimination10 was employed to predict the number of rooms having a visual assessment " failure" reported at one year post intervention. Again, the same set of possible predictors employed for predicting one year post intervention composite dust lead loading and one year post intervention composite dust lead loading exceedances of standards were used for this model. Significant predictors were the total lead hazard reduction cost at immediate post intervention ( higher costs would yield fewer rooms with " failures"), building type ( single and rowhouses would have more rooms with " failures" than multifamily buildings), whether work had been performed in the unit during the previous 12 months ( yes would yield fewer rooms with " failures"), and the estimated market value of the dwelling ( higher market values would yield fewer rooms with " failures").

X. SUMMARY OF TWO YEAR POST INTERVENTION RESULTS As discussed in the introduction to Section VI, only 24 units ( 11 LHR, 13 LHR+ W) had complete two years post intervention data. Given this small number of units, rigorous statistical testing is not considered appropriate. However, this section provides a general summary of the two years post intervention findings.

A. Two Year Post Intervention Dust Sampling Results No single surface samples were collected from any of the 24 units during two years postintervention therefore, only composite results are discussed. A complete listing of two years post intervention composite results is provided in Appendix E.

1. Summary of Two Year Post Intervention Composite Results For bare floors, median composite dust lead loadings for LHR units were slightly lower than those for LHR+ W units. However, for sills and troughs, LHR+ W units had much lower median dust lead loadings than LHR units ( See Table 49 on page 83). Based on Kruskal Wallis testing, two years post intervention median composite dust lead loadings for sills and troughs were significantly associated with assigned treatment group ( p= 0.0064 and 0.0300, respectively) but not for bare floors ( p= 0.7098).

10 In a Poisson regression model with backward elimination, the outcome of interest is a count variable ( e. g., number of failures). 11/ 23/ 05 83 Table 49: Two Year Post Intervention Composite Sample Dust Lead Loadings Surface Type LHR Dust Lead Loading ( µ g/ ft2) Median Geometric Mean 95% Confid. Limits LHR+ W Dust Lead Loading ( µ g/ ft2) Median Geometric Mean 95% Confid. Limits Bare floorsa, b ( 10 LHR units, 13 LHR+ W units) 19 27 ( 9, 85) 24 18 ( 10, 30)

Interior window sillsa, b ( 10 LHR units, 13 LHR+ W units) 568 485 ( 199; 1,186) 46 99 ( 45; 221)

Window troughsa, b ( 10 LHR units, 13 LHR+ W units) 1,710 3,119 ( 779; 12,492) 452 558 ( 235; 1,329)

Source: Form 04A, Phase IV aApproximately 96% of bare floor composites, interior window sill composites, and window trough composites were comprised of 4 sub samples; the rest were comprised of 2 sub samples. b Kruskal Wallis test indicates that median sill and trough values were significantly associated with assigned treatment group ( p= 0.0064 and 0.0300, respectively) but not the median bare floor value ( p= 0.7098).

2. Change in Composite Results from Pre to Two Years Post Intervention Large median percent decreases were observed when measuring the change in dust lead loadings from pre to two years post intervention for composite samples taken from bare floors, sills and troughs ( Table 50 on page 84). The association between the percent reduction in preintervention to two years post intervention dust lead loadings and assigned treatment group was significant for window sills ( p= 0.0008) and troughs ( p= 0.0019) but not for bare floors ( p= 0.2917). Although pre intervention window component dust lead loadings for the LHR+ W group were significantly higher than those for LHR units, at two years post intervention, the LHR+ W group had lower window component dust lead loadings. Although two year postintervention window component dust lead loadings remained lower than pre intervention loadings for LHR units, the wide confidence intervals shown in Table 49 indicate that some dwellings have rather high loadings two years after treatment. 11/ 23/ 05 84 Table 50: Median Percent Reductions and Absolute Reductions in Pre to Two Year Post Intervention Composite Dust Lead Loadings Surface Type and Statistic Composite Dust Samples LHR Units Pre to 2 Yr Post Intervention Reduction LHR+ W Units Pre to 2 Yr Post Intervention Reduction Median Percent Reduction ( 10 LHR, 13 LHR+ W) a: Bare Floors Window Sills Window Troughs 78% 79% 39% 88% 97% 96%

Median Absolute Reduction ( 10 LHR, 13 LHR+ Wa Bare Floors Window Sills Window Troughs 45 µ g/ ft2 1,960 µ g/ ft2 1,154 µ g/ ft2 170 µ g/ ft2 2,563 µ g/ ft2 10,104 µ g/ ft2 Source: Form 04A a The association between the percent reduction in pre intervention to Phase IV dust lead loadings and assigned treatment group was significant for window sills ( p= 0.0008) and troughs ( p= 0.0019) but not for bare floors ( p= 0.2917).

3. Change in Composite Results from One Year to Two Years Post Intervention Of the 24 units having two years post intervention data, only 15 ( 7 LHR and 8 LHR+ W) units had complete one year post intervention data. These numbers were too small to permit a reliable comparison of one year post intervention and two years post intervention data to be conducted. Therefore, these results are excluded from this report.

B. Results of Two Year Post Intervention Visual Assessment Too few visual assessment " failures" were observed in each treatment group to allow comparison of two years post intervention visual assessment " failures" in LHR versus LHR+ W units. Therefore, this discussion focuses on the 24 two years post intervention units as a whole. A complete listing of two years post intervention visual assessment " failures" is provided in Appendix G. Overall, 90 percent ( 22) of the 24 units having two years post intervention data had at least one visible assessment " failure" two years after treatment ( Table 51 on page 85). LAAP informed landlords of these " failures" and recommended that they be repaired.

The most common visual assessment " failure" at two years post intervention was that not all paint was intact, with 22 of the 24 units exhibiting this type of " failure". The magnitude of this " failure" was similar to that reported at one year post intervention: a geometric mean of 2 ft2 of non intact paint per unit was noted. Other " failure" types were less prevalent. For example, 10 of the 24 units reportedly had at least one door with painted surfaces rubbing together, while 9 units had some non intact or damaged kitchen and/ or bathroom floor coverings, with a geometric mean of 2 ft2 of such damage reported. Three to seven rooms per unit had some type of visual assessment " failure" at two years post intervention ( mean= 5 rooms). 11/ 23/ 05 85 Table 51: Reporting Frequency of Specified Types of Two Year Post Intervention Visual Assessment " Failures"

" Failure" Type ( 24 units) Unit of Measure # Units with Specified " Failure" Rpt'd Reporting Freq. of " Failure" Type at Ph IV " Failure" Magnit. ( Geom. Mean & 95% Conf. Limits) EAa 2 2 2 ( NA) c LF 20 58 2 ( 1, 3) Not all paint intact ( 22 units)

SF 15 47 2 ( 0.4, 5) For doors, painted surfaces continued to rub together ( 10 units) EAa 10 12 1 ( 1, 1)

Some bare floors not smooth & cleanable ( 4 units) LF SF 1 3 1 3 4 ( NA) c 2 ( 0.4, 14) Not all kitchen & bathroom floors overlaid with water resistant coverings ( 9 units) LF SF 2 7 3 9 4 ( NA) c 2 ( 1, 4)

EAb 1 4 7 ( NA) c Visible paint chips or debris remains ( 6 units) SF 5 10 1 ( 0, 82) EA= each; LF= linear foot; SF= square foot aFor these " failure" types, " each" denotes window components ( e. g., upper sash, lower sash), door casings, or handrails in need of re painting. LF/ SF values are not available for these occurrences. bFor this " failure" type, " each" usually denotes a window with debris or chips in the well. c No 95% confidence limits were calculated due to the small number of units having this failure reported.

XI. SUMMARY AND DISCUSSION OF FINDINGS The main findings of this study are that dust lead loadings declined substantially immediately after EA 6 8 prescribed lead hazard reduction treatments were implemented and remained well below pre intervention levels one year later. However, many study units would not have " passed" clearance dust samples immediately post intervention had such testing been required. The results also suggest that the independent visual inspections conducted in these units missed many lead hazard reduction treatment " failures." Although these " failures" were corrected upon discovery, several visual assessment " failures" were observed one year after treatment. Details concerning these findings are summarized below.

A. Summary and Discussion of Findings Through Immediate Post Intervention 1. Comparison of Pre and Immediate Post Intervention Dust Lead Loading Results Both the LHR and LHR+ W units were generally in poor condition and exhibited high dust lead loadings prior to the lead hazard reduction treatments. LHR+ W units had a greater number of items of interior deterioration and their pre intervention composite and single surface dust lead loadings were generally higher than those for the LHR units, indicating that LHR+ W units may have been in poorer condition than LHR units at baseline. However, after completion of the EA 6 8 prescribed treatments, both the LHR and LHR+ W units experienced substantial reductions in dust lead loading on floors, interior window sills and window troughs, as measured by either composite or single surface sampling methods. 11/ 23/ 05 86 Pre and immediate post intervention dust lead loading results for composite and single surface sampling methods are summarized in Table 52.

Table 52: Summary of Pre and Immediate Post Intervention Dust Lead Loading Results By Assigned Treatment Group and Sampling Method LHR LHR+ W Surface Type and Statistic Composite Single Surface Composite Single Surface Bare Floors: Median Pre Intervention Loading ( µ g/ ft2) Median Pre to Immed Post Int µ g/ ft2 Decrease Median Immed Post Int Loading ( µ g/ ft2) Median Pre to Immed Post Int Percent Decrease 273 147 27 85 192 99 66 70 333 225 29 89 338 226 39 88 Interior window sills: Median Pre Intervention Loading ( µ g/ ft2) Median Pre to Immed Post Int µ g/ ft2 Decrease Median Immed Post Int Loading ( µ g/ ft2) Median Pre to Immed Post Int Percent Decrease 1,986 1,686 83 94 844 497 103 84 2,780 2,596 36 99 2,350 2,516 29 99 Window Troughs: Median Pre Intervention Loading ( µ g/ ft2) Median Pre to Immed Post Int µ g/ ft2 Decrease Median Immed Post Int Loading ( µ g/ ft2) Median Pre to Immed Post Int Percent Decrease 9,427 9,708 344 95 6,135 4,111 610 94 10,998 11,284 100 > 99 12,227 12,022 115 99 Note: Because a smaller number of LHR units were single surface sampled both pre and immediate postintervention these results are possibly more uncertain even though they are consistent with single surface sample results observed for the LHR+ W units.

While none of the study units were legally required ( under EA 6 8) to undergo and pass clearance dust testing, all immediate post intervention median composite and dwelling unit average of single surface sample dust lead loading values for bare floors, interior window sills and window troughs were below the Maryland and HUD/ EPA guidance abatement " clearance" standards for such surfaces. However, when applying these clearance standards to individual single surface dust sample results, an appreciable number of LHR and LHR+ W units had at least one immediate post intervention floor, interior window sill and/ or window trough dust lead loading value that exceeded the Maryland and HUD/ EPA guidance standards ( see Table 53 on page 87). Forty six ( 46) and 28 percent of units exceeded floor clearance standards of 100 µ g/ ft2 and 200 µ g/ ft2, respectively. Eight ( 8) percent of units exceeded the interior window sill clearance standard 500 µ g/ ft2. Twenty seven ( 27) percent of units exceeded the window trough clearance standard of 800 µ g/ ft2. Assigned treatment group was significantly associated with immediate post intervention interior window sill and window trough results " passing" or " failing" their standards ( LHR+ W units generally did better) but was not significantly associated with bare floors " passing" or " failing" their respective standards. It should be noted that, had clearance testing been required, single surface dust wipe results would yield more clearance " failures" than would composite dust wipe results ( see Appendix J for more details). 11/ 23/ 05 87 Table 53: Percentage of Units with Immediate Post Intervention Single Surface Clearance " Failures" Percent of Units within Specified Category Surface Type: Floors Interior Window Sills Window Troughs Std/ Guidance:

100 µ g/ ft2

200 µ g/ ft2

500 µ g/ ft2

800 µ g/ ft2 LHR Units 60% 35% 20% 50% LHR+ W Units 41% 25% 5% 19% Total All Units 46% 28% 8% 27%

2. Immediate Post Intervention Visual Assessment Results Although statistically significant dust lead loading reductions from pre to immediate postintervention were observed, immediate post intervention confirmatory visual assessments performed by the LAAP inspectors suggest that a high percentage of study units ( 93 percent of LHR and LHR+ W units combined) had " failures" of one or more of the prescribed lead hazard reduction treatments and, as such, would have " failed" to meet the EA 6 8 risk reduction standard. This is noteworthy since each one of the 121 study units passed the independent visual inspection conducted shortly before the LAAP confirmatory visual assessments.

In addition, the reported " failures" were large enough to be easily observed. For the most commonly reported " failure"  not all paint intact  a dwelling unit geometric mean of 1 ft2 of non intact paint was reported in LHR and in LHR+ W units. Visible paint chips and debris remaining at clearance was also quite frequently reported, with a dwelling unit geometric mean of 8 ft2 noted in LHR units and 16 ft2 in LHR+ W units. Door surfaces continuing to rub together were also frequently reported at an average of 1 door per unit.

Of these 121 units, 27 percent would have " failed" one ( 1) of the prescribed lead hazard reduction treatment types, another 36 percent would have " failed" two ( 2) of the prescribed treatment types and an additional 23 percent would have " failed" three ( 3) of the prescribed treatment types. For both LHR and LHR+ W units, the most prevalent " failure" types were: not all paint intact, with some chipping, flaking and peeling paint remaining ( 75 percent of all units); one or more painted doors continuing to rub together and/ or bind ( 43 percent); and visible paint chips and/ or debris remaining ( 38 percent). Additionally, in 26 percent of the LHR units, not all window trough cap material was properly attached.

In those units that " failed" the LAAP inspectors' visual assessment at immediate postintervention considering only those rooms with " failures" applicable to both LHR and LHR+ W units, an average of 3.1 rooms in the LHR units and 2.6 rooms in the LHR+ W units had " failures."

These results suggest that, at least for this study group, lead hazard reduction treatments did not completely meet the prescribed risk reduction standard and more strongly suggest that the independent visual inspections conducted in these units failed to identify all lead hazard reduction treatment " failures," even ones that should have been easily observed ( e. g., 71 ft2 of visible chips/ debris). Because only five or six independent inspectors conducted visual inspections in the group of 121 study units, this finding does not necessarily reflect on all other 11/ 23/ 05 88 Maryland certified inspectors but does indicate that these five or six inspectors missed important items.

3. Cost Data Analysis Results Two factors potentially impacted the lead hazard reduction treatment costs recorded for the 121 study units:

  " Adverse selection" of enrolled units. The majority of the study units were in poor condition to begin with ( e. g., extensive deferred maintenance resulted in a high degree of interior and exterior deterioration), which likely resulted in higher costs. Because property owners could receive a grant for up to 80 percent of the total lead hazard control costs, they may have deliberately enrolled units that needed more extensive work, either due to deferred maintenance or the length of time since last rental turnover.

  Effect of participating in the study. Since property owners and contractors were aware that the enrolled units were being evaluated for the study, it is possible that extra effort may have gone into the lead hazard reduction treatments, thereby potentially inflating reported treatment costs. ( Interestingly, even if this was the case, it was not borne out by the LAAP inspectors' visual assessment results.)

Window replacement also added appreciably to the total lead hazard reduction treatment costs recorded for the LHR+ W units. While median costs for only the prescribed lead hazard reduction treatments were $ 2,154 and $ 1,649 for LHR and LHR+ W units, respectively, the median lead treatment plus window replacement cost for LHR+ W units was $ 4,348; this represents an approximate two fold increase in the total LHR+ W lead costs.

Speculating that the recorded costs were higher than expected for a typical Baltimore City rental housing unit, Center and LAAP representatives met with a local rental property owner to discuss his firm's experience in complying with the EA 6 8 risk reduction standard. On average, this owner's total expense of performing the prescribed treatments at first unit turnover costs from $ 700 to $ 900 per unit. Subsequent turnover prescribed treatment costs typically run from $ 300 to $ 400 per unit. The initial expenses that are added to this owner's normal unit turnover regimen include HEPA vacuuming the entire unit ($ 80), window treatments ($ 35 to $ 40 per window unit), re hanging and re working doors ($ 20 to $ 25 per door), and the cost of a visual inspector ($ 35 to $ 40 per inspection). According to this owner, normal unit turnover expenses, exclusive of the required lead related costs, can run as high as $ 5,000 to $ 6,000 per unit, depending on the length of time the unit has been occupied by one tenant and/ or the amount of tenant related damage. ( The owner counts interior repainting as a normal turnover expense.)

Considering the factors that potentially inflated recorded costs and reflecting on the typical experience of a Baltimore City rental property owner in complying with the statute, the lead hazard reduction treatment costs recorded by this study should not be considered average and/ or representative of all Baltimore City rental housing units. 11/ 23/ 05 89 B. Summary and Discussion of Findings Through Two Years Post Intervention 1. Comparison of Pre Intervention and One Year Post Intervention Dust Lead Loading Results Prior to prescribed lead hazard reduction treatments, both the LHR and the LHR+ W units in the 73 unit dataset ( followed through one year) were generally in poor condition and exhibited high dust lead loadings. During the one year post intervention period, only six ( 6) of the 73 units reportedly had further lead hazard reduction work done. At one year post intervention, composite dust lead loadings on bare floors, window sills and window troughs remained far below pre intervention levels in both treatment groups. Median percent reductions in composite dust lead loadings from pre intervention to one year post intervention on sills and troughs in LHR+ W units were significantly different from and lower than those in LHR units. The median percent reduction in composite dust lead loadings for bare floors in LHR+ W units was about the same as in LHR units.

At one year post intervention, single surface dust lead loadings on floors, sills and troughs remained far below pre intervention levels for LHR+ W units, the only treatment group having single surface data at one year post intervention.

Pre and one year post intervention dust lead loading results for composite and single surface sampling methods are summarized in Table 54.

Table 54: Summary of Pre and One Year Post Intervention Dust Lead Loading Results By Assigned Treatment Group and Sampling Method LHR LHR+ W Surface Type and Statistic Composite Single Surface Composite Single Surface Bare Floors: Median Pre Intervention Loading ( µ g/ ft2) Median µ g/ ft2 Reduction Median 1 Yr Post Intervention Loading ( µ g/ ft2) Median Percent Reduction 120 87 22 82% NA NA NA NA 454 335 20 94% 440 420 20 96% Interior window sills: Median Pre Intervention Loading ( µ g/ ft2) Median µ g/ ft2 Reduction Median 1 Yr Post Intervention Loading ( µ g/ ft2) Median Percent Reduction 1,739 713 449 82% NA NA NA NA 2,930 2,803 121 97% 1,987 1,875 64 97% Window Troughs: Median Pre Intervention Loading ( µ g/ ft2) Median µ g/ ft2 Reduction Median 1 Yr Post Intervention Loading ( µ g/ ft2) Median Percent Reduction 10,219 4,507 1,074 89% NA NA NA NA 12,524 12,014 247 98% 17,083 16,338 211 99% NA= Not applicable. Single surface samples were collected in only two LHR units at Phase III; therefore, no single surface results are presented for LHR units. 11/ 23/ 05 90 For bare floor and sills, one year post intervention median composite dust lead loadings were less than HUD clearance standards of 100 and 500 µ g/ ft2, respectively. Median composite dust lead loadings for troughs in LHR+ W units were also less than the HUD standard of 800 µ g/ ft2, but the median composite trough result for LHR units exceeded this standard. At one year postintervention 14% of LHR+ W units had at least one single surface floor dust lead result exceeding a clearance standard of 100 µ g/ ft2, 17% had at least one single surface sill result greater than 500 µ g/ ft2 and 14% had at least one single surface trough result above 800 µ g/ ft2 ( see Table 55).

Comparison of LHR+ W clearance exceedance rates with those of Baltimore HUD units studied during the National Evaluation yielded some surprising results. Although LHR+ W units appeared to be in worse condition at baseline and Baltimore HUD units had similar treatments and clearance testing immediately after intervention, LHR+ W units appeared to be in better condition one year later based on single surface dust wipe results. This finding is possibly due to the correction of treatment " failures" in LHR+ W units after the immediate post intervention visit. Median percent reductions from pre to one year post intervention were generally greater for LHR+ W units than for Baltimore HUD units, possibly due to the worse initial condition of floors and troughs. LAAP reported that the correction of Phase II treatment " failures" sometimes entailed re cleaning if the correction potentially generated dust ( e. g., if painted doors had to be planed).

Table 55: Percentage of Units with One Year Post Intervention Single Surface Clearance " Failures" Percent of Units within Specified Category Surface Type: Floors Interior Window Sills Window Troughs Std/ Guidance:

100 µ g/ ft2

200 µ g/ ft2

500 µ g/ ft2

800 µ g/ ft2 LHR+ W Units ( 36 units) 14% 11% 17% 14%

Balt. HUD Units ( 249 units) 57% NA 11% 35%

2. One Year Post Intervention Visual Assessment Results Although immediate post intervention treatment " failures" were corrected and one year postintervention median composite dust lead loadings in a majority of units were less than clearance standards, a high percentage of units ( 96%) had at least one visual assessment " failure" reported one year after treatments were completed. These " failures" were widespread, with non intact paint reported in 68 units, painted door surfaces rubbing together in 30 units, visible paint chips and debris in 21 units, deterioration of kitchen and bathroom floor water resistant coverings in 20 units, and bare floors not smooth and cleanable in nine ( 9) units. Such " failures" tended to be of small magnitude but were large enough to be easily observed, with geometric means of 1 ft2 of non intact paint reported per unit, one rubbing painted door problem per unit, 4 ft2 of bare floors that were not smooth and cleanable, 2 ft2 of deteriorated kitchen/ bathroom floor water resistant coverings, and 1 ft2 of visible paint chips and debris present one year after interventions. As previously stated, the areal density ( i. e., depth) and lead concentration of chips/ debris were not measured. These visual assessment results suggest that, at least for this study group, lead hazard 11/ 23/ 05 91 reduction treatments did not remain completely intact one year after lead hazard reduction treatments.

3. Comparison of Pre Intervention and Two Years Post Intervention Dust Lead Loading Results Two years after lead hazard reduction treatments were first performed, composite dust lead loadings on all surfaces remained well below pre intervention levels ( Table 56). Of the 24 units having two years post intervention data, only 15 had complete one year post intervention data; therefore, no comparison of one year post intervention and two years post intervention data could be made.

Table 56: Summary of Pre and Two Years Post Intervention Compositea Dust Lead Loading Results By Assigned Treatment Group and Sampling Method Surface Type and Statistic LHR LHR+ W Bare Floors: Median Pre Intervention Loading ( µ g/ ft2) Median Pre to 2 Yr Post Int µ g/ ft2 Reduction Median 2 Yr Post Intervention Loading ( µ g/ ft2) Median Pre to 2 Yr Post Int Percent Reduction 139 45 19 78% 177 170 24 88% Interior window sills: Median Pre Intervention Loading ( µ g/ ft2) Median Pre to 2 Yr Post Int µ g/ ft2 Reduction Median 2 Yr Post Intervention Loading ( µ g/ ft2) Median Pre to 2 Yr Post Int Percent Reduction 2,201 1,960 568 79% 2,930 2,563 46 97% Window Troughs: Median Pre Intervention Loading ( µ g/ ft2) Median Pre to 2 Yr Post Int µ g/ ft2 Reduction Median 2 Yr Post Intervention Loading ( µ g/ ft2) Median Pre to 2 Yr Post Int Percent Reduction 3,408 1,154 1,710 39% 10,900 10,104 452 96% aSingle surface samples were not collected in any units at Phase IV; therefore, no single surface results are presented.

C. Comparing the Efficacy of the Prescribed Lead Hazard Reduction Treatments Both With and Without Window Replacement When measured by the immediate post intervention visual assessments and composite and single surface dust lead loading results, pre intervention lead hazards in the LHR+ W units were more effectively reduced than in the LHR units. Although LHR+ W units had more baseline building and dwelling unit deterioration and higher dust lead loadings prior to the intervention, these trends were reversed slightly immediately after treatment. Replacement of windows may account for these observed immediate post intervention results, particularly with respect to interior window sill and window trough dust lead loadings. This is supported by the results of predictive modeling, which showed that pre intervention dust lead loadings on sills and troughs, as well as treatment group assignment, significantly predicted immediate post intervention dust lead loadings on sills and troughs. 11/ 23/ 05 92 At immediate post intervention, the LHR+ W units had fewer lead hazard reduction treatment visual assessment " failure" types per unit and fewer rooms per unit with " failures." Also, the mean number of " failure" types per LHR unit, which was greater than the LHR+ W units, was found to be statistically significant for treatment group assignment ( p value = 0.0255).

For both composite and single surface sampling methods, immediate post intervention median bare floor dust lead loading results were similar for LHR and LHR+ W units. However, for interior window sills and window troughs, both the composite and single surface immediate postintervention sample results were significantly associated with the assigned treatment group, and were substantially lower in the LHR+ W units. This finding indicates that window replacement is much more effective in reducing lead dust hazards on window surfaces within the unit immediately after treatment.

Although LHR+ W units had more baseline building and dwelling unit deterioration and higher dust lead loadings than LHR units prior to intervention, at one year post intervention, LHR+ W units tended to have lower dust lead loadings and greater percent reductions in dust lead loadings on window sills and troughs between pre and one year post intervention than did LHR units. Little difference in one year post intervention bare floor dust lead loadings, however, was discernible between the two treatment groups. Replacement of windows likely accounts for these observed one year post intervention results, as is supported by the results of predictive modeling, which showed that pre intervention sill dust lead loadings, as well as treatment group assignment, significantly predicted one year post intervention dust lead loadings on sills and troughs. Assigned treatment group did not significantly predict one year post intervention bare floor dust lead loadings; the only significant predictor of one year bare floor dust lead loadings was the percent of rooms with visual assessment " failures."

Although differences in dust lead loadings at one year post intervention were observed, visual assessment " failures" for LHR units were generally similar to those observed for LHR+ W units. While there were marginally significant differences in the mean number of visual assessment " failures" per unit for LHR ( 2.4) versus LHR+ W units ( 1.9) ( p= 0.0482), there was no significant association between the types of visual assessment " failures" and the assigned treatment group and the magnitude of " failures" was generally very similar between the two groups.

These findings indicate that window replacement is more effective in maintaining lower dust lead loadings on window surfaces within the unit one year after treatment.

XII. CONCLUSIONS AND RECOMMENDATIONS A. Conclusions The primary research goals of this study were to evaluate the efficacy of the EA 6 8 lead hazard reduction treatments in reducing dust lead loading, both alone and in combination with window replacement. Overall, results through immediate post intervention showed that dust lead loadings were significantly reduced on floors, interior window sills and window troughs. Additionally, results through one year post intervention showed that the levels remained low one year after treatment, with over 80 percent of units having floor, sill and trough dust lead loadings 11/ 23/ 05 93 that were below clearance standards. However, immediately after the treatment intervention, many units would have " failed" clearance dust testing had it been required in the statute. More importantly, a substantial number of units " failed" the LAAP inspectors' visual assessments at immediate post intervention, despite the fact that each of the 121 study units passed the prescribed independent inspector's visual inspection.

By addressing the five ( 5) key evaluation questions found in Section II. B, additional conclusions can be made:

1. How effective are the EA 6 8 prescribed treatments in reducing dust lead loading on floors, interior window sills and window troughs to acceptable levels?

Although dramatic decreases in dust lead loadings on all surface types were found immediately post intervention, remaining dust lead loadings were high. As discussed in Section I. A, although EA 6 8 does not require clearance dust testing upon completion of the prescribed treatments, study results strongly suggest that visual inspections alone, as performed by independent visual inspectors under current oversight conditions, are not sufficient to assure that housing units will be safe for re occupancy by families with young children.

Applying the same HUD/ EPA guidance clearance standards of 100 µ g/ ft2 for floors, 500 µ g/ ft2 for interior window sills and 800 µ g/ ft2 for window troughs that were used to determine dust clearance " failures" in the HUD Lead Hazard Control Grant Program National Evaluation, immediate post intervention single surface dust sample " failure" rates were high in the study units. Forty six ( 46) percent of the units had at least one sample that " failed" floor clearance, eight ( 8) percent had at least one sample that " failed" interior window sill clearance and 27 percent had at least one sample that " failed" window trough clearance. This is a higher " failure" rate than that observed for vacant Baltimore Round One units enrolled in the HUD Evaluation ( i. e., 29 percent for floors, one ( 1) percent for interior window sills and six ( 6) percent for window troughs).

HUD recently promulgated a new lead based paint regulation governing all pre 1978 housing receiving federal assistance as well as federally owned housing. The regulation includes new clearance standards applicable to such housing. Applying these clearance standards of 40 µ g/ ft2 for floors, 250 µ g/ ft2 for interior window sills and 400 µ g/ ft2 for window troughs to the immediate post intervention single surface dust sample results recorded during this study, 73 percent of the study units would have had at least one sample that " failed" floor clearance, 15 percent would have had at least one sample that " failed" interior window sill clearance and 38 percent would have had at least one sample that " failed" window trough clearance.

Considering that the study units were not randomly selected and that property owners, contractors and independent visual inspectors were all presumably aware that the units would undergo dust testing as part of this study, these high clearance " failure" rates support the need for clearance dust testing in conjunction with the prescribed treatments. 11/ 23/ 05 94 2. To what extent does lead dust re accumulate on these surfaces over a one and two year period after completion of the treatments?

Overall, one year post intervention results showed that dust lead loadings on floors, sills and troughs remained far below pre intervention levels. Although one year post intervention dust lead loadings were dramatically less than pre intervention levels for all three surface types, several units had floor, sill and trough composite dust sample results that exceeded HUD clearance standards of 100, 500, and 800 µ g/ ft2, respectively, and many had visual assessment " failures" one year after interventions were complete.

Replacement of windows in units that also underwent the prescribed treatments resulted in substantially lower dust lead loadings on sills and troughs one year after completion of treatments, but no significant differences in bare floor dust lead loadings were observed between LHR+ W and LHR units. These results indicate that lead hazard reduction interventions that include window replacement are more effective than those that simply treat windows ( Table 57).