Dermal exposures to CWPs are not quantifiable using the EPA dermal exposure models for liquids and solids (these models are only applicable to dermal exposure to uncured resin, which may occur upstream of the press in the CWP manufacturing process).
Exposure Assessment for Wholesale
This section presents and discusses the assessment of formaldehyde exposures from the wholesale of composite wood products.
Description of Life Cycle Stage
Wholesalers buy products from manufacturers in bulk for the purpose of resale to various industries and individuals.  Wholesale products may include composite wood products and CWP fabrication products (downstream products).  A single wholesaler may sell many different types of composite wood products.  The U.S. Census Bureau defines wholesale facilities as those who "sell or arrange the purchase or sale of capital or durable goods to other businesses" (Census 2007a).  However, IMIS data, which are presented in Section 4.3.3, indicate that some wholesale facilities may also process composite wood products on site (the reported worker activities at wholesale facilities include "sawing").
Use Volumes and Number of Establishments, Employees, Employed Hours, and Work Days
Information related to the number of sites, number of employees, and facility-specific use rates (including storage and wholesale) of composite wood products and CWP fabrication articles made of composite wood products were researched.  Data for the number of sites and employees from the 2007 U.S. Economic Census are provided in the EPA market profile (USEPA 2010a).  However, actual loading data of the total emitting surface area of composite wood products at wholesale settings were not found.  Table 4-16 summarizes the census data identified for wholesale facilities that may sell composite wood products or articles fabricated from composite wood products as obtained from the EPA market profile.  It is uncertain whether all facilities in the identified NAICS codes sell composite wood products or downstream articles made of composite wood products.  Therefore, the number of sites and employees identified in Table 4-16 may represent wholesalers that do not use composite wood products and are considered maximum values.

Table 4-16.  Summary of 2007 Economic Census Data for Wholesale Facilities
                                  NAICS Code
                          NAICS Industry Description
                       Maximum Number of Establishments
                       Maximum Number of Paid Employees
                                                                         423210
Furniture merchant wholesalers
                                                                          6,640
                                                                         69,103
                                                                         423220
Home furnishing merchant wholesalers
                                                                          7,540
                                                                         93,060
                                                                         423310
Lumber, plywood, millwork, and wood panel merchant wholesalers
                                                                          8,428
                                                                        138,739
                                                                         423320
Brick, stone, and related construction material merchant wholesale
                                                                          3,383
                                                                         35,005
                                                                         423330
Roofing, siding, and insulation material merchant wholesalers
                                                                          2,587
                                                                         32,662
                                                                         423390
Other construction material merchant wholesalers
                                                                          3,383
                                                                         37,920
                                                                         423440
Other commercial equipment merchant wholesalers
                                                                          4,352
                                                                         48,976
                                                                         423450
Medical equipment merchant wholesalers
                                                                          8,282
                                                                        141,282
                                                                         423490
Other professional equipment and supplies merchant wholesalers
                                                                          2,297
                                                                              D
                                                                         423510
Metal service centers and other metal merchant wholesalers
                                                                         10,148
                                                                        144,954
                                                                         423610
Elec. equip. and wiring merchant wholesalers
                                                                         13,277
                                                                        169,355
                                                                         423620
Electric appliance merchant wholesalers
                                                                          3,110
                                                                         44,819
                                                                         423710
Hardware merchant wholesalers
                                                                          6,828
                                                                         83,542
                                                                         423720
Plumbing equip. merchant wholesalers
                                                                          6,939
                                                                         86,092
                                                                         423730
HVAC equip. merchant wholesalers
                                                                          5,071
                                                                         50,495
                                                                         423740
Refrigeration equipment and supplies merchant wholesalers
                                                                          1,265
                                                                         11,024
                                                                         423830
Industrial machinery and equipment merchant wholesalers
                                                                         29,838
                                                                        319,557
                                                                         423850
Service establishment equipment and supplies merchant wholesalers
                                                                          4,576
                                                                          D[10]
                                                                         423910
Sporting and recreational goods and supplies merchant wholesalers
                                                                          6,192
                                                                         55,842
                                                                         424610
Plastics materials and basic forms and shapes merchant wholesaler
                                                                          3,248
                                                                         32,552
                                                                         424950
Paint, varnish, and supplies merchant wholesalers
                                                                          1,649
                                                                         14,631
   Source: EPA market profile (USEPA 2010a)

Pre-Baseline Exposure Monitoring Data
Formaldehyde monitoring data for various worker activities at various wholesale settings were obtained from the OSHA IMIS database (OSHA 2009a).  Only two data points from a single wholesale site classified under one of the NAICS codes identified in Table 2-1 were available for the pre-baseline period (2002 to 2009).  Table 4-17 presents these data by worker activity.
Table 4-17. Summary of Formaldehyde Inhalation Monitoring Data for Wholesalers from the OSHA IMIS Database
                                   Industry
                          Worker Activity Description
                           Number of Sites Monitored
                  Monitored Formaldehyde Concentration (ppm)
              Monitored Formaldehyde Concentration (ug/m[3])[1]
                                Monitoring Type
                                     Year
Furniture Merchant Wholesalers
Band Saw Operator
                                       1
                                     0.002
                                     2.46
                                   Personal
                                     2003

                                 Not Detected
                                 Not Detected
                                   Personal
                                     2003

Panel Saw Operator

                                     0.002
                                     2.46
                                   Personal
                                     2003

CNC Operator

                                 Not Valid[2]
                                   Not Valid
                                   Personal
                                     2003
 [1] The formaldehyde concentration in ug/m[3] was calculated from the provided concentration in ppm by multiplying the concentration in ppm by 1,229 ug/m[3]/ppm (see Appendix E).
 [2] Data point reported as "not valid" in the IMIS database; likely an invalid measurement.

Baseline Exposure and the Effect of Analytical Options on Baseline Exposure for Wholesale
Exposures in wholesale settings are not assessed quantitatively due to data gaps.  There is a lack of information on the ventilation rate at wholesale settings to allow for a what-if analysis similar to what was completed for the fabrication life cycle stage.  Therefore, it is not possible to accurately quantify the exposure concentrations during the baseline period and the reduction of exposure concentrations resulting from the analytical options.
The formaldehyde concentration resulting from off-gassing is expected to decrease with the implementation of more stringent regulations.  However, as discussed previously, the implementation of CARB ATCM Phase 1 limits is expected to result in little or no reduction in exposure from the baseline year.  This is because most composite wood products in the market would already be meeting more stringent limits by 2013.
Dermal Exposures during Wholesale
Dermal exposures to CWPs are not quantifiable using the EPA dermal exposure models for liquids and solids.
Exposure Assessment for Retail
This section presents and discusses the assessment of formaldehyde exposures from retail due to composite wood products.
Description of Life Cycle Stage
Retailers operate from fixed locations and sell products for direct consumption by the purchaser (individuals or businesses).  These retailers may receive HWPW, MDF, or PB directly as products or included in articles fabricated using composite wood products.  Like wholesale sectors, retail sectors are not distinguished by composite wood product type (Census 2007a).
Use Volumes and Number of Establishments, Employees, Employed Hours, and Work Days
Information related to the number of sites, number of employees, and facility-specific use rates (including storage and retail) of composite wood products and CWP fabrication products were researched.  The number of sites and employees data from the 2007 U.S. Economic Census (Census 2007a) was identified.  However, actual loading data of the total emitting surface area of composite wood products at wholesale settings were not found.  Table 4-18 summarizes the census data identified for retail facilities that may sell composite wood products or articles fabricated from composite wood products.  It is uncertain whether all facilities in the identified NAICS codes sell composite wood products or downstream articles made of composite wood products.  Therefore, the number of sites and employees identified in Table 4-18 may represent retailers that do not use composite wood products and are considered maximum values.
The duration and frequency of exposure were assumed to be 8 hours per day and 250 days per year, respectively.  This is supported to some extent by IMIS data on duration.  Some exposure data points in IMIS do not include an exposure duration and other data points include an exposure duration of "daily" or other frequency without comment on the number of hours of exposure per day.  For retail, 17 exposure data points (sampled in 2002 through 2009) were collected.  For these 17 data points, the following exposure duration data were included in IMIS:
Exposure durations of blank or "daily": seven data points (41%);
Exposure durations of eight hours per day: three data points (18%);
Exposure duration of three hours per week: one data point (6%);
Exposure duration of 40 hours per week: three data points (18%); and
Exposure duration of "monthly", "routinely", or "varies": three data points (18%).

Table 4-18.  Summary of 2007 Economic Census Data for Retail Facilities
                                    NAICS
                                     Code
                          NAICS Industry Description
                                Maximum Number
                               of Establishments
                                Maximum Number
                               of Paid Employees
                                    441210
Recreational vehicle dealers
                                                                          3,100
                                                                         42,669
                                    442110
Furniture stores
                                                                         28,834
                                                                        266,374
                                    442210
Floor covering stores
                                                                         14,534
                                                                         89,420
                                    442291
Window treatment stores
                                                                          2,652
                                                                          9,626
                                    442299
All other home furnishings stores
                                                                         19,124
                                                                        192,057
                                    443111
Household appliance stores
                                                                          9,336
                                                                         70,045
                                    443112
Radio, television, and other electronics stores
                                                                         29,051
                                                                        309,374
                                    443120
Computer and software stores
                                                                         10,428
                                                                         92,777
                                    444110
Home centers
                                                                          6,953
                                                                        579,442
                                    444120
Paint and wallpaper stores
                                                                          7,860
                                                                         35,491
                                    444130
Hardware stores
                                                                         16,454
                                                                        143,738
                                    444190
Other building material dealers
                                                                         39,551
                                                                        405,755
                                    444210
Outdoor power equipment stores
                                                                          4,357
                                                                         25,882
                                    444220
Nursery, garden center, and farm supply stores
                                                                         15,895
                                                                        141,014
                                    445110
Supermarkets and other grocery (except convenience) stores
                                                                         64,881
                                                                      2,432,425
                                    448110
Men's clothing stores
                                                                          8,321
                                                                         57,340
                                    448120
Women's clothing stores
                                                                         36,220
                                                                        339,798
                                    448130
Children's and infants' clothing stores
                                                                          7,102
                                                                         98,729
                                    448140
Family clothing stores
                                                                         28,254
                                                                        642,117
                                    448150
Clothing accessories stores
                                                                          7,494
                                                                         37,575
                                    448190
Other clothing stores
                                                                         12,034
                                                                         97,581
                                    451120
Hobby, toy, and game stores
                                                                          9,357
                                                                        135,688
                                    451130
Sewing, needlework, and piece goods stores
                                                                          5,663
                                                                         49,450
                                    452111
Department stores (except discount department stores)
                                                                          3,533
                                                                        534,189
                                    452112
Discount department stores
                                                                          5,001
                                                                        690,265
                                    452910
Warehouse clubs and supercenters
                                                                          4,260
                                                                      1,244,237
                                    452990
All other general merchandise stores
                                                                         33,061
                                                                        294,783
                                    453110
Florists
                                                                         19,822
                                                                         93,967
                                    453210
Office supplies and stationery stores
                                                                          9,558
                                                                        112,734
                                    453220
Gift, novelty, and souvenir stores
                                                                         31,391
                                                                        193,317
                                    453920
Art dealers
                                                                          6,677
                                                                         23,126
                                    453930
Manufactured (mobile) home dealers
                                                                          3,878
                                                                         21,068
                                    453998
All other miscellaneous store retailers (except tobacco stores)
                                                                         17,270
                                                                         88,296
                                    454113
Mail-order houses
                                                                          7,324
                                                                        220,516
                                    454390
Other direct selling establishments
                                                                         22,077
                                                                        131,013
Source: EPA market profile (USEPA 2010a)

Pre-Baseline Exposure Monitoring Data
Formaldehyde exposure monitoring data for various worker activities at various retail settings obtained from the OSHA IMIS database (OSHA 2009a) for the period of 2002 to 2009 are presented in Table 4-19.  Pre-baseline data are available for seven retail sectors only, and for most only a single monitoring data point is available.  A total of 17 data points are available for the entire sector during the pre-baseline period.

Table 4-19.  Summary of Formaldehyde Inhalation Monitoring Data for Retailers from the OSHA IMIS Database
                                   Industry
                          Worker Activity Description
                           Number of Sites Monitored
                             Number of Data points
                  Monitored Formaldehyde Concentration (ppm)
              Monitored Formaldehyde Concentration (ug/m[3])[1]
                                Monitoring Type
                                     Year
Recreational Vehicle Dealers
Sawing
                                       1
                                       1
0.002
2.46
Personal
                                     2006
Furniture Stores
Cabinet Maker
                                       1
                                       1
0.069
84.8
Personal
                                     2002

Front Right of Store
                                       1
                                       5
Not Detected [2]
Not Detected [2]
Area
                                     2008

Front Left of Store

Not Detected [2]
Not Detected [2]
Area
                                     2008

Back Left of Store

Not Detected [2]
Not Detected [2]
Area
                                     2008

Back Right of Store

Not Detected [2]
Not Detected [2]
Area
                                     2008

Middle of Store

Not Detected [2]
Not Detected [2]
Area
                                     2008
All Other Home Furnishing Stores
Sale
                                       1
                                       1
0.017
20.9
Area
2006
Radio, Television & Other Electronic Stores
Warehouse Handler
                                       1
                                       1
0.14
172.1
Personal
2004
Home Centers
Cabinet Maker/Painter
                                       1
                                       1
0.00001 [2]
0.012 [2]
Personal
2007
Other Building Material Dealers
Laminator
                                       1
                                       1
0.055
67.6
Personal
2003

Painting
                                       1
                                       1
0.1
122.9
Personal
2008

Operator

                                       1
0.19
233.5
Personal
2008

Driver
                                       1
                                       1
Not Detected [2]
Not Detected [2]
Area
2004

Sales Rep
                                       1
                                       1
Not Detected [2]
Not Detected [2]
Area
2002
Department Stores (except Discount Department Stores)
Merchandise Coordinator
                                       1
                                       1
Not Detected [2]
Not Detected [2]
Area
2003

Unpack Clothing
                                       1
                                       1
Not Detected [2]
Not Detected [2]
Area
2006
 [1] The formaldehyde concentration in ug/m[3] was calculated from the provided concentration in ppm by multiplying the concentration in ppm by 1,229 ug/m[3]/ppm (see Appendix E).
 [2] The minimum reliable quantitation limit (RQL) identified for OSHA sampling and analysis methods is 0.00058 ppm.  Non-detected values and values below this RQL are set equal to the RQL for the exposure calculations.

Baseline Exposure and the Effect of Analytical Options on Baseline Exposure for Retail
Exposures in retail settings are not assessed quantitatively due to data gaps.  There is a lack of information on the ventilation rate at retail settings to allow for a what-if analysis similar to what was completed for the fabrication life cycle stage.  Therefore, it is not possible to accurately quantify the exposure concentrations during the baseline period and the reduction of exposure concentrations resulting from the analytical options.
The formaldehyde concentration resulting from off-gassing is expected to decrease with the implementation of more stringent regulations.  However, as discussed previously, the implementation of CARB ATCM Phase 1 limits is expected to result in little or no reduction in exposure from the baseline year.  This is because most composite wood products in the market would already be meeting more stringent limits by 2013.
Although the U.S. Census Bureau defines the retail trade sector as "establishments engaged in retailing merchandise, generally without transformation, and rendering services incidental to the sale of merchandise," the limited IMIS data indicate that sawing, assembling, building, painting, and other laboring activities are performed at some retail facilities.  A further search of one facility reported in the IMIS suggests that some fabrication sites could be involved in direct retail.  For example, one company makes custom cabinets and sells these cabinets to builders, dealers, and consumers.  This company is classified under NAICS 444190: "Other Building Material Dealers."  The exposures at fabrication sites have been assessed in Section 4.2.
Dermal Exposures during Retail
Dermal exposures to CWPs are not quantifiable using the EPA dermal exposure models for liquids and solids.
Exposure Assessment for Office Workers during Commercial Use
This section presents and discusses the assessment of formaldehyde exposures resulting from the occupancy of office buildings (commercial buildings) containing composite wood products by office workers.
Description of Life Cycle Stage
The commercial use of composite wood products includes the occupancy by office workers of office buildings (commercial buildings) containing composite wood products.  These office workers may be exposed to airborne formaldehyde emitted from CWPs or CWP fabrication products that are present in the commercial building.
Use Volumes and Number of Establishments, Employees, Employed Hours, and Work Days
Data that provide inventories of each composite wood product within commercial office buildings were not found.  Additionally, census data that provide the number of commercial use sites, the total number of employees, and employee hours worked per day and days worked per year in office settings were not found.  These data are difficult to obtain as commercial use settings, such as office buildings, occur across multiple industries.  For example, the industries described in the upstream life cycle stages in this report (manufacturing, wholesale, retail) all may involve office settings in addition to the settings described in their respective sections above.
Pre-Baseline Exposure Monitoring Data
This section provides pre-baseline indoor air concentration monitoring data obtained from the BASE study from 1994 to 1998.  These data are presented to compare to the model results presented in the next subsection.  Table 4-20 presents some general characteristics of the 100 commercial and public office buildings collected from the BASE study, including the construction date, floor area, number of floors and occupants.
Table 4-20.  Overview of General Characteristics of the 100 BASE Buildings
                             Characteristic (unit)
                                     Range
                                    Average
                                    Median
Construction Date (year)
                                  1850 - 1996
                                     1961
                                     1972
Gross Floor Area (m[2])
                                1,665 - 134,195
                                    24,756
                                    13,964
Occupied Floor Area (m[2])
                                 629 - 98,474
                                    16,380
                                     8,477
Number of Floors Above Grade
                                   1  -  53
                                       9
                                       5
Number of Building
Occupants (including visitors)
                                 87  -  6,500
                                     1,020
                                      705
  Source: BASE 1998a

Formaldehyde was detected in a quantifiable amount in all 100 buildings.  Table 4-21 presents a summary of the monitored formaldehyde concentrations in office buildings that were obtained from the BASE study (BASE 1998a).  The study only presented the overall formaldehyde concentrations within the buildings and did not distinguish exposures according to worker activities.  Table 4-21 also provides the summary statistics of the monitored outdoor formaldehyde concentrations from the BASE study, which were measurements made outside of the office buildings.
Table 4-21.  Summary of Formaldehyde Inhalation Monitoring Data for Office Occupational Settings and Outdoor Measured Concentrations from the BASE Study
                                  Percentile
                     Formaldehyde Concentration (ug/m[3])
                       Formaldehyde Concentration (ppm)

                                    Indoors
                                   Outdoors
                                    Indoors
                                   Outdoors
100[th] (Maximum)
                                      51
                                      13
                                     0.041
                                     0.011
95[th]
                                      32
                                      10
                                     0.026
                                     0.008
75[th]
                                      21
                                      5.7
                                     0.017
                                     0.005
50[th] (Median)
                                      15
                                      3.0
                                     0.012
                                     0.002
25[th]
                                      9.2
                                      1.4
                                     0.007
                                     0.001
5[th]
                                      4.4
                                     0.40
                                     0.004
                                     0.000
Arithmetic Mean
                                      16
                                      3.9
                                     0.013
                                     0.003
Source: BASE 1998a

Baseline Exposure and the Effect of Analytical Options on Baseline Exposure for Office Buildings
What-if values for indoor air concentrations in an office building related to baseline and the analytical options were estimated using mathematical modeling.  The mathematical modeling for indoor air concentration is presented in Section <IP_ADDRESS> and described in detail in Appendix E.
The estimation results are given in Table 4-22.  The results in Table 4-22 are for the three limiting cases of the office workstation being fabricated from 100% HWPW, 100% PB, and 100% MDF.  These results were combined into a single range, which is given in Table 4-23.
The range of what-if indoor air concentrations given in Table 4-23 is the estimate of the range of values for the steady-state indoor air formaldehyde concentration in a work space resulting from the off-gassing emissions from new HWPW, PB, and MDF components of the workstation occupying the work space and due to the ventilation with outside air containing ambient formaldehyde.  The emitting surface area of each workstation component and the ventilation rate of the work space containing the workstation are values given in BIFMA M7.1-2007  -  "Standard Test Method for Determining VOC Emissions from Office Furniture Systems, Components and Seating".
In homes, the most significant sources of formaldehyde are likely to be CWPs made from UF resins (USEPA 2011b).  The literature search did not identify information to indicate that sources of formaldehyde in office buildings are significantly different than in homes.  Therefore, it is assumed that CWPs are the most significant source of formaldehyde in office buildings.
Office building ventilation systems likely contain a recirculation component, which results in the mixing of air from various sections of the office building with outside air and the subsequent recirculation of the mixed air throughout the office building.  Thus, the formaldehyde concentration in any given work space can be affected by the formaldehyde concentration in other sections of the office building.  The mathematical modeling does not account for this effect.
Determination of a Best Estimate for Indoor Air Concentration
The best estimate exposure concentrations, ADC, and LADC results are presented in Table 4-26.  The best estimate exposure concentrations for the baseline and each analytical option were determined by averaging the following values: the midpoint of the intermediate range of concentrations for open plan workstations and the midpoint of the intermediate range of concentrations for private office workstations.  The midpoints of the intermediate ranges of concentration estimates were used for the following reasons.  First, all of the high-end concentration estimates at the baseline are on the order of or greater than 0.1 ppm for both workstation types.  Indoor air in buildings with a formaldehyde concentration of 0.1 ppm is considered highly polluted air.  It is not likely that typical office buildings will have workstations with highly polluted air at the baseline even if the buildings do use new furniture.  Second, the low-end concentration estimates at the baseline and for each analytical option are on the order of 0.003 to 0.005 ppm for both workstation types.  The ambient air formaldehyde concentration for commercial land use areas used for this assessment is 3.26 ug/m[3] or about 0.00265 ppm.  The low-end concentration estimates are the same order of magnitude as the ambient air formaldehyde concentration.  It is likely that formaldehyde concentrations in office buildings at the baseline would be greater than the ambient air formaldehyde concentration.  Therefore, the intermediate range of concentration estimates is more reasonable in comparison with the low- and high-end ranges and was used to derive the best estimate concentrations.  The midpoints of the intermediate ranges for both workstation types are averaged together to provide the best estimate concentrations.  The best estimate reduction from baseline, ADC, and LADC values are calculated from the best estimate concentration values.  It is assumed that office workers spend most of their time at workstations.  Therefore, this indoor air concentration is the exposure concentration for office workers.  As described in Appendix E, ADC and LADC were calculated assuming exposure duration of 8 hours per day and exposure frequency of 250 days per year over 40 working years per lifetime for ADC and over a lifetime of 70 years for LADC.
Similarly as with the CWP fabrication results, the office building results show that the maximum formaldehyde exposure concentration decreases as lower (more stringent) emission standards are implemented.  Again, the minimum exposure concentrations in Table 4-22 and Table 4-23 remain constant throughout the different analytical options due to the presence of NAF-compliant products at the baseline.  The office building results in Table 4-26 show the most significant reduction in exposure concentration from the NAF emission limits.

Table 4-22.  Results for Calculation of What-If Indoor Air Formaldehyde Concentrations for Each Analytical Option
                                     Case
                                   CWP Type
                               Low-End of Range
                              Intermediate Value
                               High-End of Range
                        Open Plan Workstations (ppm)[1]
Baseline
HWPW
                                    0.0035
                                    0.0265
                                    0.2002

PB
                                    0.0035
                                    0.0346
                                    0.4680

MDF
                                    0.0053
                                    0.0732
                                    1.0089
Analytical Option (1): CARB Phase 1
HWPW
                                  0.0035 (0%)
                                0.0167 (-36.8%)
                                0.0729 (-63.6%)

PB
                                  0.0035 (0%)
                                0.0328 (-5.2%)
                                0.1117 (-76.1%)

MDF
                                  0.0053 (0%)
                                0.0705 (-3.7%)
                                0.2833 (-71.9%)
Analytical Option (2): FSCWPA / CARB Phase 2
HWPW
                                  0.0035 (0%)
                                0.0143 (-45.9%)
                                0.0414 (-79.3%)

PB
                                  0.0035 (0%)
                                0.0323 (-6.7%)
                                0.0717 (-84.7%)

MDF
                                  0.0053 (0%)
                                0.0701 (-4.2%)
                                0.1670 (-83.4%)
Analytical Option (3): NAF
HWPW
                                  0.0035 (0%)
                                0.0099 (-62.5%)
                                0.0184 (-90.8%)

PB
                                  0.0035 (0%)
                                0.0099 (-71.3%)
                                0.0184 (-96.1%)

MDF
                                  0.0053 (0%)
                                0.0346 (-52.8%)
                                0.0728 (-92.8%)
                     Private Office Workstations (ppm)[1]
Baseline
HWPW
                                    0.0030
                                    0.0130
                                    0.0719

PB
                                    0.0030
                                    0.0165
                                    0.1659

MDF
                                    0.0036
                                    0.0332
                                    0.3555
Analytical Option (1): CARB Phase 1
HWPW
                                  0.0030 (0%)
                                0.0087 (-32.5%)
                                0.0273 (-62.0%)

PB
                                  0.0030 (0%)
                                0.0157 (-4.7%)
                                0.0409 (-75.3%)

MDF
                                  0.0036 (0%)
                                0.0320 (-3.5%)
                                0.1011 (-71.6%)
Analytical Option (2): FSCWPA / CARB Phase 2
HWPW
                                  0.0030 (0%)
                                0.0077 (-40.6%)
                                0.0163 (-77.4%)

PB
                                  0.0030 (0%)
                                0.0155 (-6.1%)
                                0.0269 (-83.8%)

MDF
                                  0.0036 (0%)
                                0.0318 (-4.0%)
                                0.0603 (-83.0%)
Analytical Option (3): NAF
HWPW
                                  0.0030 (0%)
                                0.0058 (-55.3%)
                                0.0082 (-88.6%)

PB
                                  0.0030 (0%)
                                0.0058 (-64.8%)
                                0.0082 (-95.1%)

MDF
                                  0.0036 (0%)
                                0.0165 (-50.4%)
                                0.0273 (-92.3%)
Note: For the purpose of this assessment, "intermediate" is defined as a value in-between the low-end and the high-end (see Section <IP_ADDRESS>).
[1] For the analytical options, the percent decrease from the corresponding baseline value is given in parentheses.  For example, for Analytical Option (1) for open plan workstations, the high-end value for HWPW is 0.0729 ppm - a 63.6 percent decrease from the high-end baseline value.

Table 4-23.  Combined (for All CWP) Results: Calculated What-If Indoor Air Concentrations at the Baseline and for the Analytical Options
                           Open Plan Workstations[1]
                                     Case
                              Intermediate (ppm)
                                 Low End (ppm)
                                High End (ppm)
Baseline
                                0.0265 - 0.0732
                                0.0035 - 0.0053
                                0.2002 - 1.0089
Phase 1
                       0.0167 (-37.0%) - 0.0705 (-3.7%)
                           0.0035 (0%) - 0.0053 (0%)
                       0.0729 (-63.6%) - 0.2833 (-71.9%)
FSCWPA / Phase 2
                       0.0143 (-46.0%) - 0.0701 (-4.2%)
                           0.0035 (0%) - 0.0053 (0%)
                       0.0414 (-79.3%) - 0.167 (-83.4%)
NAF
                       0.0099 (-62.6%) - 0.0346 (-52.7%)
                           0.0035 (0%) - 0.0053 (0%)
                       0.0184 (-90.8%) - 0.0728 (-92.8%)
                        Private Office Workstations[1]
                                     Case
                              Intermediate (ppm)
                                 Low End (ppm)
                                High End (ppm)
Baseline
                                0.013 - 0.0332
                                0.003 - 0.0036
                                0.0719 - 0.3555
Phase 1
                        0.0087 (-33.1%) - 0.032 (-3.6%)
                           0.003 (0%) - 0.0036 (0%)
                       0.0273 (-62.0%) - 0.1011 (-71.6%)
FSCWPA / Phase 2
                       0.0077 (-40.8%) - 0.0318 (-4.2%)
                           0.003 (0%) - 0.0036 (0%)
                       0.0163 (-77.3%) - 0.0603 (-83.0%)
NAF
                       0.0058 (-55.4%) - 0.0165 (-50.3%)
                           0.003 (0%) - 0.0036 (0%)
                       0.0082 (-88.6%) - 0.0273 (-92.3%)
[1] For the analytical options, the percent decrease from the corresponding baseline value is given in parentheses.  For example, for Analytical Option (1) for open plan workstations, the minimum of the high-end values is 0.0729 ppm - a 63.6 percent decrease from the high-end baseline value.

Table 4-24.  Combined (for All CWP) Results: Calculated What-If Indoor Air ADCs at the Baseline and for the Analytical Options
                            Open Plan Workstations
                                     Case
                            Intermediate (ug/m[3])
                              Low End (ug/m[3])
                              High End (ug/m[3])
Baseline
                                 7.44 - 20.54
                                  0.98 - 1.49
                                 56.17 - 283.1
Phase 1
                                 4.69 - 19.78
                                  0.98 - 1.49
                                 20.46 - 79.49
FSCWPA / Phase 2
                                 4.01 - 19.67
                                  0.98 - 1.49
                                 11.62 - 46.86
NAF
                                  2.78 - 9.71
                                  0.98 - 1.49
                                 5.16 - 20.43
                          Private Office Workstations
                                     Case
                            Intermediate (ug/m[3])
                              Low End (ug/m[3])
                              High End (ug/m[3])
Baseline
                                  3.65 - 9.32
                                  0.84 - 1.01
                                 20.17 - 99.75
Phase 1
                                  2.44 - 8.98
                                  0.84 - 1.01
                                 7.66 - 28.37
FSCWPA / Phase 2
                                  2.16 - 8.92
                                  0.84 - 1.01
                                 4.57 - 16.92
NAF
                                  1.63 - 4.63
                                  0.84 - 1.01
                                  2.3 - 7.66

Table 4-25.  Combined (for All CWP) Results: Calculated What-If Indoor Air LADCs at the Baseline and for the Analytical Options
                            Open Plan Workstations
                                     Case
                            Intermediate (ug/m[3])
                              Low End (ug/m[3])
                              High End (ug/m[3])
Baseline
                                 4.25 - 11.74
                                  0.56 - 0.85
                                 32.1 - 161.8
Phase 1
                                  2.68 - 11.3
                                  0.56 - 0.85
                                 11.69 - 45.42
FSCWPA / Phase 2
                                 2.29 - 11.24
                                  0.56 - 0.85
                                 6.64 - 26.78
NAF
                                  1.59 - 5.55
                                  0.56 - 0.85
                                 2.95 - 11.67
                          Private Office Workstations
                                     Case
                            Intermediate (ug/m[3])
                              Low End (ug/m[3])
                              High End (ug/m[3])
Baseline
                                  2.08 - 5.32
                                  0.48 - 0.58
                                 11.53 - 57.00
Phase 1
                                  1.39 - 5.13
                                  0.48 - 0.58
                                 4.38 - 16.21
FSCWPA / Phase 2
                                  1.23 - 5.1
                                  0.48 - 0.58
                                  2.61 - 9.67
NAF
                                  0.93 - 2.65
                                  0.48 - 0.58
                                  1.31 - 4.38

Table 4-26.  Best Estimate of What-If Formaldehyde Exposure Concentration at the Baseline and for the Analytical Options
                                     Case
                      Best Estimate Concentration1 (ppm)
                          Reduction from Baseline (%)
                                 ADC (ug/m3)
                                 LADC (ug/m3)
Baseline
                                    0.0365
                                      --
                                     10.23
                                     5.85
Phase 1
                                    0.0320
                                     -12.3
                                     8.97
                                     5.13
FSCWPA / Phase 2
                                    0.0310
                                     -15.1
                                     8.69
                                     4.97
NAF
                                    0.0167
                                     -54.2
                                     4.69
                                     2.68
            [1] The best estimate concentration is the average of the following two values: the midpoint of the intermediate range for open plan workstations and the midpoint of the intermediate range for private office workstations. The reduction from baseline, ADC, and LADC values are calculated from the best estimate concentration value.

Dermal Exposures during Commercial Use
Dermal exposures to CWPs are not quantifiable using the EPA dermal exposure models for liquids and solids.

Uncertainties In Assessment Results
Uncertainties in Assessment Results for Composite Wood Product Manufacturing, Fabrication, Wholesale, Retail, and Office Buildings
This section discusses the uncertainties in the results of the assessment of occupational formaldehyde exposure at composite wood product manufacturing, fabrication, wholesale, and retail sites, and office buildings.  Baseline indoor air concentration and the effect of the analytical options on it were assessed quantitatively for CWP fabrication and office buildings only, and therefore the discussion of uncertainty in the assessment of indoor air concentration is limited to these life cycle stages and is presented in Section 5.1.1 and Section 5.1.2, respectively.  Uncertainty in the assessed number of production workers for the manufacturing and fabrication life cycle stages and in the number of employees in the wholesale and retail life cycle stages is discussed in Section 5.3.
Dermal exposures were assessed quantitatively for manufacturing.  Due to data gaps in information on the free (un-reacted) formaldehyde content in resins that will be used at baseline and for each analytical option, only pre-baseline dermal exposures were estimated for manufacturing.  The dermal exposure level at the baseline and for the analytical options was assumed to be equal to the estimated pre-baseline dermal exposure level.  This assumption would overestimate the dermal exposures at baseline and the analytical options if the free formaldehyde content of resins is lower at the baseline and for the analytical options.
Uncertainty in the Estimates of Indoor Air Concentration for Composite Wood Product Fabrication
The assessment of site-average formaldehyde indoor air concentrations for composite wood product fabrication relies on a mass balance approach that equates the emission rates due to off-gassing to the rate at which airborne formaldehyde is exhausted from the work space through ventilation.  As discussed in Section <IP_ADDRESS> and Appendix E, indoor air concentration was calculated from the four parameters in the mass balance equation, which are emitting surface area, emission rate due to off-gassing, effective ventilation rate, and ambient air formaldehyde concentration, as well as the assumption of a well-mixed box for the fabrication site.  As discussed in Section <IP_ADDRESS>, due to data gaps on the values of these four parameters at representative CWP fabrication sites, a range of what-if values for indoor air concentration was calculated from bounding values for the ranges of three of the four parameters.  CWP fabrication sites were assumed to contain only HWPW, or only PB, or only MDF in this what-if approach.  As discussed in Section <IP_ADDRESS>, there is considerable uncertainty in the range of values for emitting surface area, and some uncertainty in the ranges of values for effective ventilation rate and for emission rates.  Therefore, there is uncertainty in the calculated ranges of baseline indoor air concentration due to off-gassing and the effect of the analytical options on the baseline concentrations.  It is not possible to determine the direction of uncertainty (i.e., whether the estimated values for indoor air concentration are an underestimate or an overestimate).
Although IMIS data and emission rates for the pre-baseline period are available, they cannot be used to perform a general validation of the calculation method nor can this information be used to estimate values for effective ventilation rate and emitting surface area for the following reasons:
The calculated assessment results are only an estimate of airborne concentrations due to off-gassing.  IMIS monitoring data are intended to be measurements of aggregate airborne concentrations and do not contain information on the source or sources of exposure and the contributions to the aggregate concentrations where different sources of exposure existed when the monitoring occurred.
It is uncertain as to whether the IMIS monitoring data are representative of the exposures experienced by workers in the CWP fabrication industries during the pre-baseline period (see Section 5.2.1).

The modeling method used to estimate formaldehyde concentrations in this assessment only accounts for the off-gassing of formaldehyde from the three composite wood products of interest and the formaldehyde concentration in ambient air.  As discussed in Section 4.2.1, there is some indication that sources other than the three CWPs of interest may contribute to formaldehyde airborne concentrations.  The number of sites in which these other sources may be present, the number of workers that would be potentially exposed to emissions from these other sources, and the magnitude of such potential exposure are not known.  The assessment results for the baseline and analytical options are not an estimate of aggregate indoor air concentration where other sources of formaldehyde exist.
Uncertainty in the Estimates of Indoor Air Concentration for Office Buildings
Data on the composition of composite wood products in office furniture was not found.  Therefore, the composition of each of the three types of composite wood products in office workstations is unknown.  As discussed in Section <IP_ADDRESS>, panels and work surfaces were assumed to be wholly made of composite wood products.  Information on the type and extent of overlays on the composite wood products was also not found.  The effect of uncertainty about the composition of CWPs in office workstations and the overlays on these CWPs on the assessment of baseline exposure and the effect of analytical options on baseline exposure are undetermined.
The office building method uses emission rates for new composite wood products and do not account for the decay of emissions with time.  Therefore, this method to estimate formaldehyde concentrations in office buildings only accounts for new office furniture and does not account for the decay of emission rates with time.  Data to describe the decay of emission rates with time in office buildings were not found through the literature search.  Therefore, the estimated airborne concentrations presented in this assessment are only applicable to offices with new office furniture.
The method used simplifies the complex nature of office building ventilation systems.  Typically in these systems, outdoor air is mixed with a recirculation stream of indoor air prior to being supplied to the various ventilation zones.  The return air from these ventilation zones is mixed and then a stream is split for recirculation and mixing with the outdoor air while the balance is exhausted.  Therefore, the office environment model neglects the effect of one exposure zone on another resulting from the recirculation of indoor air or the movement of air directly between exposure zones without passing through the ventilation system.  The uncertainty in the results due to neglecting the effect of one exposure zone on another is uncertain and cannot be quantified without a detailed, rigorous mathematical model with detailed supporting monitoring data.
Although monitoring data from the BASE study and emission rates for the 2002 to 2009 pre-baseline period are available, they cannot be used to perform a general validation of the calculation method or a validation of the assumed values for the surface area covered by overlay materials and their associated barrier effectiveness.  The ages of the office furniture workstations present in the buildings studied in the BASE study are unknown.  It is likely that much of the office furniture that contributed to the exposure concentrations observed in the BASE study were of various ages and not representative of new office furniture.  The emission rates for CWP that are components of this aged office furniture at the time of monitoring are not known because their initial value when these CWP were new is not known and the extent of their decay with time until the time of monitoring is not known.  Furthermore, even where monitoring occurred for new office furniture (a situation that cannot be determined from the BASE study data), the emission rates of CWPs used in this furniture is unknown.  Hence, model validation is not possible using the BASE study data because the emission rates of CWPs present in office furniture in the monitored buildings is unknown.
Uncertainties in Pre-Baseline Monitoring Data
OSHA IMIS Data
This section discusses uncertainties associated with OSHA IMIS monitoring data.  The uncertainties discussed below apply to the IMIS data collected for each life cycle stage (CWP manufacturing, fabrication, wholesale, and retail).  The major conclusion of this discussion is that it is uncertain whether the collected IMIS data are representative of the formaldehyde exposure concentrations that occurred during the pre-baseline period of 2002 to 2009 in facilities of the industries within each life cycle stage assessed in this report.
Representativeness of IMIS Data
The representativeness of the measured exposure concentrations in IMIS for the entire population of exposed workers is examined below.  The discussion below presents statistics of the IMIS data obtained for the CWP fabrication life cycle stage only since a larger amount of data were obtained for this life cycle stage.  Very few data were obtained for the CWP manufacturing, wholesale, and retail life cycle stages.
Table 5-1 presents data on the total number of unique OSHA inspections conducted within each NAICS industry code of the CWP fabrication life cycle stage.  A total of 78 inspections were conducted at 77 facilities between 2002 and 2009, indicating that most inspections occurred at separate facilities.  The table compares the number of inspected facilities to the total number of facilities for that particular industry sector based on estimates from the 2007 Economic Census.  The sample size (the number of inspected facilities) ranges from zero to 19 over all of the industries.  Sampling theory guarantees an accurate degree of confidence in the estimate of a population mean when the sample size is at least 30 samples.  When at least 30 samples are obtained, it is not required for the population to have a normal distribution to guarantee an accurate degree of confidence.  However, accuracy does require that the samples are random (Walpole 2002a).
Table 5-1.  Number of OSHA Inspections at CWP Fabrication Facilities Compared to the Maximum Number of Facilities from the U.S. Economic Census
                                     NAICS
                                  Description
                        2007 U.S. Economic Census Data
                         OSHA IMIS Data (2002 to 2009)

                       Maximum Number of Establishments
                         Number of Unique Inspections
                          Number of Unique Facilities
321911
Wood window & door Manufacturing
                                     1,494
                                       4
                                       4
321918
Other millwork (including flooring)
                                     2,101
                                       9
                                       9
321991
Manufactured home (mobile home) Manufacturing
                                      376
                                       0
                                       0
321999
All other misc. wood product Manufacturing
                                     1,964
                                       8
                                       8
337110
Wood kitchen cabinet & countertop Manufacturing
                                     9,683
                                      20
                                      19
337121
Upholstered household furniture Manufacturing
                                     1,633
                                       4
                                       4
337122
Nonupholstered wood household furniture Manufacturing
                                     3,428
                                      12
                                      12
337124
Metal household furniture Manufacturing
                                      330
                                       0
                                       0
337127
Institutional furniture Manufacturing
                                      782
                                       5
                                       5
337129
Wood television, radio, & sewing machine cabinet Manufacturing
                                      270
                                       0
                                       0
337211
Wood office furniture Manufacturing
                                      457
                                       6
                                       6
337212
Custom architectural woodwork & millwork Manufacturing
                                     2,228
                                       2
                                       2
337214
Office furniture (except wood) Manufacturing
                                      289
                                       2
                                       2
337215
Showcase, partition, shelving, & locker Manufacturing
                                     1,377
                                       5
                                       5
339950
Sign manufacturing
                                     6,383
                                       0
                                       0
336213
Motor home Manufacturing
                                      80
                                       1
                                       1
336214
Travel trailer & camper Manufacturing
                                      862
                                       0
                                       0
                                                                          Total
                                    33,737
                                      78
                                      77

For each fabrication industry, less than 30 samples were obtained between 2002 and 2009.  Therefore, an accurate degree of confidence in the estimate of the population mean cannot be guaranteed without knowledge of whether the population is represented by a normal distribution.  While all of the fabrication industries in Table 5-1 can be aggregated together to yield a sample size of 78 (the total number of inspections), such aggregation would not resolve the second criterion for an accurate degree of confidence: random sampling.  Examination of the randomness of the sampling is made using knowledge of how OSHA conducts inspections.
Lavoue et al. (Lavoue 2008a) analyzed formaldehyde exposures from U.S. industries from the OSHA IMIS database using data from 1979 to 2001.  The authors note that exposures in IMIS have long been suspected to not be representative of exposures in the U.S. population.  The authors found the IMIS exposures to mainly result from complaints, referrals, or programs targeted at specific industrial sectors.  However, the authors also note that, "within industries, available evidence suggests that bias relating to selecting companies with high exposure levels during complaint visits should be of small amplitude".  The pre-baseline exposure monitoring data presented in the assessment were examined to further evaluate any selection bias.
OSHA may initiate an inspection due to a referral by a federal or state government agency or a worker complaint regarding workplace hazards.  Alternatively, OSHA may inspect establishments that were selected under the agency's programmed inspection plan.  The "inspection types" for the compiled IMIS data are: (1) referral (15%); (2) complaint (58%); (3) program-planning (25%); and (4) follow-up (2%) (see Appendix A, Definition of Terms for exposure and inspection types).  These inspection types are further discussed below.
The Site-Specific Targeting program is OSHA's main programmed inspection plan for non-construction workplaces that have 40 or more workers.  The selection criteria involve several parameters such as the number of injury and illness cases, the number of days away from work, and the number of workers who receive job transfers or work restrictions due to injury or illness.  In addition to the Site-Specific Targeting program, OSHA also implements both national and local emphasis inspection programs to target high-risk hazards and industries.  Some areas that OSHA focuses on are amputations, lead, crystalline silica, shipbreaking, trenching and excavations, process safety management in petroleum refineries, hexavalent chromium, diacetyl, recordkeeping and combustible dust (OSHA 2010a).  Programmed and planned inspections may or may not be considered random.  If a particular industry were chosen for a programmed or planned inspection, the facilities inspected within the selected industry would have been chosen randomly.  However, it is possible a facility was specifically chosen as part of a program or plan if the facility had a history of problems or hazards, in which case the choice of facility would not have been random.
Complaint and referral inspection types would not be considered random, since OSHA inspected the given facility based on evidence that a problem existed from an employee or other agency with knowledge of the facility.  It is difficult to determine whether follow-up inspections would be considered random without knowing the inspection type for the original inspection.
Although OSHA typically inspects establishments with potential workplace hazards, these hazards may or may not be related to formaldehyde overexposure.  For example, OSHA may inspect an establishment that manufactures PB after an employee files a complaint concerning dust exposure.  Since the establishment processes formaldehyde-containing materials, personal monitoring for formaldehyde was also conducted during the inspection although there may or may not be a formaldehyde overexposure.  Therefore, it cannot be assumed that a facility inspected by OSHA through one of the programs described above is necessarily an outlying or atypical facility with high formaldehyde exposures.
It is uncertain whether the programmed and planned inspections included in the IMIS data presented in this assessment randomly selected the inspected facilities.  Therefore, it cannot be concluded whether any of the OSHA IMIS data are the result of random sampling.  In conclusion, it is uncertain whether OSHA IMIS monitoring data are representative of the exposure concentrations of formaldehyde in the industries from which the data were obtained.
Intra-Site Variability in Monitored Indoor Air Concentration
This subsection discusses the variability in the measured indoor air concentrations during a single inspection at a single facility.  This discussion is limited to CWP fabrication sites since only this life cycle stage had an adequate amount of data to allow this analysis.
The variation in indoor air concentration of fabricator sites was considered by examination of IMIS monitoring data.  Figure 5-1 through Figure 5-8 display formaldehyde indoor air concentrations from OSHA IMIS for composite wood product fabricators in which multiple worker activities were monitored for a single site.  The graphs display formaldehyde concentration as a function of monitored worker activity.  CSHO stands for Compliance Safety and Health Officer and represents the exposures for the inspector.  Worker activities with only a single exposure level are shown with only a median exposure concentration measurement.
These figures illustrate that many of these site inspections resulted in similar exposure concentrations for all monitored worker activities (exposure level for the worker activity with the highest exposure level is typically greater than the exposure level of the worker activity with the lowest exposure level by up to approximately 100%).  However, for some sites, there are worker activities with greater variation than this, including the frame operator at Armstrong Cabinets, the painter U cell at The Gunlocke Company, and the August 25th auto spray line at Silver Street.  Most of these have higher values than the other measurements.  Most of the pre-baseline monitoring data presented in the assessment consist of multiple measurements for a single worker activity at a given site.  There is considerable variability in the monitored worker activities from site to site.
In conclusion, intra-site variability in the monitored exposure level ranges from small to as much as 100% or greater based on examination of IMIS data for which multiple worker activities at a single site were monitored.

Figure 5-1.  TWA Exposures from OSHA IMIS for a Single Inspection for Armstrong Cabinets (NAICS 337110)

Figure 5-2.  TWA Exposures from OSHA IMIS for a Single Inspection for Mid Continent Cabinetry (NAICS 337110)

Figure 5-3.  TWA Exposures from OSHA IMIS for a Single Inspection for Benvenuti and Stein (NAICS 337122)

Figure 5-4.  TWA Exposures from OSHA IMIS for a Single Inspection for Ameriwood Industries (NAICS 337122)

Figure 5-5.  TWA Exposures from OSHA IMIS for Two Inspections for The Gunlocke Company (NAICS 337211)

Figure 5-6.  TWA Exposures from OSHA IMIS for Two Inspections for Silver Street (NAICS 337211)

Figure 5-7.  TWA Exposures from OSHA IMIS for a Single Inspection for The Commercial Furniture Group (NAICS 337127)

Figure 5-8.  TWA Exposures from OSHA IMIS for a Single Inspection for Parenti & Raffaelli (NAICS 321918)

BASE Study Monitoring Data
A total of 100 commercial and public office buildings were monitored in the BASE study between 1994 and 1998.  To determine the representativeness of the BASE sample of office buildings, the BASE study authors compared this sample to larger samples of U.S. office buildings using data collected by the Energy Information Administration of the U.S. Department of Energy through the 1995 Commercial Building Energy Consumption Survey (CBECS).  The BASE study authors were able to perform two comparisons: 1) a comparison of the BASE buildings to a larger sample of large urban office buildings; and 2) a comparison of the BASE buildings to a larger sample of all U.S. office buildings.  The BASE study authors determined that the BASE buildings are most similar to the CBECS sample of large, urban office buildings; specifically, buildings with more than 50 occupants in Metropolitan Statistical Areas (MSAs) (BASE 2001a).  The BASE study authors note that the BASE buildings were selected from cities with populations greater than 100,000.  However, MSAs are urbanized areas with populations greater than 50,000.  Therefore, there is a slight discrepancy in the comparison of the surrounding populations of the BASE study buildings and the large, urban office buildings from CBECS.  Furthermore, the BASE buildings were selected from downtown areas.  The BASE study authors found the BASE buildings to be three to four times larger than the CBECS sample of large, urban office buildings.  Consistent with this finding, a separate survey conducted by the Building Owners and Managers Association (BOMA) found that downtown office buildings tend to be larger than other metropolitan area office buildings.  Although these differences in surrounding population and building size are noted, the BASE study authors found that BASE study buildings most likely represent large, urban office buildings (BASE 2001a).
Based on the CBECS sample of all U.S. office buildings, the BASE buildings do not represent the entire population of all U.S. office buildings well.  However, the BASE study authors note that, although the large, urban office buildings account for only 11% (or about 80,000) of all U.S. office buildings (about 705,000), this building type represents 73% (or about 19,428,229) of all U.S. office workers (about 26,563,566) according to the CBECS data (BASE 2001a).  Therefore, the BASE study office buildings are most similar to the office building type (large, urban office buildings) that house approximately 73% of all U.S. office workers.  Note that these statistics are based on survey data from 1995.  It is unknown how these statistics have changed since 1995.  The second criterion, random sample selection, is analyzed next.
The building selection criteria described in the BASE study documents indicate that the BASE study did randomly select office buildings for study.  Buildings were selected randomly in randomly selected cities.  The study authors selected buildings in ten climatic regions of the U.S. (BASE 2001a; NIST 2008a).
Whether the measured formaldehyde concentrations are representative of year-round concentrations in these buildings is also analyzed.  The BASE study focused its building measurements during the winter and summer months.  Building ventilation systems are more likely to operate at minimum outdoor air ventilation rates during the winter and summer to minimize the amount of air heating or cooling required.  NIST conducted an analysis of the ambient temperatures recorded during the BASE study and concluded that approximately 62% of the data could possibly correspond to buildings operating with minimum outdoor air ventilation rates (NIST 2008a).  However, the building operations during winter and summer were not compared against their operations during spring or autumn.  Therefore, it cannot be concluded for certain whether buildings were operating at lower outdoor air ventilation rates during the BASE study.  NIST additionally analyzed the BASE study data on the ventilation system designs and the measured ventilation rates.  NIST concluded that the ratio of the minimum outdoor air ventilation rate to total supply air ventilation based on the ventilation system designs had an average value of 0.19 and a median of 0.12.  The observed ratio of actual outdoor air ventilation rate to total supply air ventilation had an average value of 0.38 and a median of 0.22 (NIST 2008a).  This observation illustrates that, in general, many of the studied buildings operated at outdoor air ventilation rates greater than the system design minimum.
In conclusion, it has been established that the studied buildings are representative of large, urban commercial and public office buildings from the time frame of the study.  However, it is uncertain whether the measured formaldehyde concentrations are representative of concentrations that occurred in these buildings during an entire year or if they are only representative of winter and summer concentrations.
Uncertainty in Number of Production Workers and Employees
U.S. Census data on the number of production workers (for CWP manufacturing and fabrication) and employees (for wholesale and retail) are presented for the NAICS industry sectors associated with each life cycle stage.  While these data were not used for the quantitative assessment, they were presented to indicate the total number of production workers and employees potentially exposed to formaldehyde emissions from composite wood products.  These data likely represent an overestimation for the following reasons.
Census data represent the overall statistics for the entire industry sector.  Additionally, Census data do not contain specific information on the type of composite wood products associated with these statistics.  Some sites within these industry sectors may not manufacture, use, or sell the composite wood products of interest.
For any given site, it is uncertain whether the breathing zone for all production workers or employees would be affected by the off-gassing of formaldehyde from the composite wood products of interest.  Therefore, there is some uncertainty in assessing whether the number of production workers and employees presented in this assessment is an overestimate.  However, for the reasons listed above, the number of production workers and employees from U.S. Census data is likely an overestimate of the actual exposed population who would be affected by the regulation.  More specific information on the actual exposed population is not available.

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Hamilton 1996a. Hamilton, Thomas E.; Alig, Joanne T.; Falk, Robert H. Products from Recycled Fibers  -  A U.S. Perspective, Proceedings of the International Union of Forest Research Organizations (IUFRO) XX World Congress, Tampere, Finland, August 6-12, 1995. November 21, 1996. http://www.metla.fi/iufro/iufro95abs/rsp21.htm.
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Hodgson 2007a. Hodgson, Alfred T.; Tannous, Raja S. Meeting the Requirements of the California Composite Wood ATCM Using Chambers of Different Sizes; Berkeley Analytical Associates, LLC: Richmond, CA, September 7, 2007.
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IRSST undated. Exposure to Formaldehyde in the Workplace: Wood Furniture Manufacturing; Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST): Montréal, Québec, undated.
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Lavoue 2008a. Lavoué, Jérôme; Vincent, Raymond; Gérin, Michel. Formaldehyde Exposure in U.S. Industries from OSHA Air Sampling Data. Journal of Occupational and Environmental Hygiene 2008, 5, 575-587.
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OAQPS 1997a. Hanks, Katie; Bullock, David. Site Visit  -  Champion International Corporation Camden Plywood and Stud Operations, Camden, Texas; Memorandum from Midwest Research Institute to U.S. Environmental Protection Agency (USEPA), Office of Air Quality and Planning Standards (OAQPS): December 1, 1997.
OAQPS 1998a. Hanks, Katie; Nicholson, Becky. Site Visit  -  Timber Products Company Particleboard and Hardwood Plywood Plant in Medford, Oregon; Memorandum from Midwest Research Institute to U.S. Environmental Protection Agency (USEPA), Office of Air Quality and Planning Standards (OAQPS): April 16, 1998.
OAQPS 1998b. Hanks, Katie; Nicholson, Becky. Site Visit  -  Medite Division of Sierra Pine Medium Density Fiberboard Plant in Medford, Oregon; Memorandum from Midwest Research Institute to U.S. Environmental Protection Agency (USEPA), Office of Air Quality and Planning Standards (OAQPS): May 27, 1998.
OAQPS 1998c. Hanks, Katie; Bullock, David. Site Visit  -  Triwood, Incorporated Particleboard Plant in Bassett, Virginia; Memorandum from Midwest Research Institute to U.S. Environmental Protection Agency (USEPA), Office of Air Quality and Planning Standards (OAQPS): August 18, 1998.
OAQPS 1999a. Hanks, Katie; Threatt, Brigit; Nicholson, Becky. Summary of Responses to the 1998 EPA Information Collection Request (MACT Survey)  -  Hardwood Plywood and Veneer; Development of a NESHAP for Plywood and Composite Wood Products Manufacturing Industry; Memorandum from Midwest Research Institute to U.S. Environmental Protection Agency (USEPA), Office of Air Quality and Planning Standards (OAQPS): May 19, 1999.
OAQPS 1999b. Bullock, David; Nicholson, Becky; Threatt, Brigit. Site Visit  -  Willamette Industries, Incorporated, Moncure, North Carolina; Memorandum from Midwest Research Institute to U.S. Environmental Protection Agency (USEPA), Office of Air Quality and Planning Standards (OAQPS): July 27, 1999.
OAQPS 2000a. Hanks, Katie; Bullock, David; Nicholson, Becky. Summary of Responses to the 1998 EPA Information Collection Request (MACT Survey)  -  General Survey; Development of a NESHAP for Plywood and Composite Wood Products Manufacturing Industry; Memorandum from Midwest Research Institute to U.S. Environmental Protection Agency (USEPA), Office of Air Quality and Planning Standards (OAQPS): April 28, 2000.
OAQPS 2000b. Background Information Document for Proposed Plywood and Composite Wood Products NESHAP; EPA-453/R-01-004; U.S. Environmental Protection Agency (USEPA), Office of Air Quality and Planning Standards (OAQPS): Research Triangle Park, NC, September 2000.
OAQPS 2002a. Economic Impact Analysis of the Plywood and Composite Wood Products NESHAP: Final Report; U.S. Environmental Protection Agency (USEPA), Office of Air Quality and Planning Standards (OAQPS): Research Triangle Park, NC, November 2002.
OAQPS 2002b. Compilation of Air Pollutants Emission Factors, Volume I: Stationary Point and Area Sources (AP-42), Chapter 10, Wood Products Industry; U.S. Environmental Protection Agency (USEPA), Office of Air Quality and Planning Standards (OAQPS): 2002. http://www.epa.gov/ttnchie1/ap42/ch10/.
OECA 1995a. EPA Office of Compliance Sector Notebook Project: Profile of the Wood Furniture and Fixtures Industry; EPA/310-R-95-003; U.S. Environmental Protection Agency (USEPA), Office of Enforcement and Compliance Assurance (OECA), Office of Compliance: Washington, DC, September 1995.
OSHA 1999a. Inspection Report for McKnight Plywood, West Helena, AR; Inspection number 123445595; U.S. Department of Labor, Occupational Safety and Health Administration (OSHA): Little Rock, AR, August 30, 1999.
OSHA 2000a. Inspection Report for Carolina Curves, Inc., Conover, NC; Inspection number 303713325; North Carolina Department of Labor, Division of Occupational Safety and Health: Charlotte, NC, August 15, 2000.
OSHA 2000b. Inspection Report for Jimson Manufacturing Company, Inc., Haleyville, AL; Inspection number 303424014; U.S. Department of Labor, Occupational Safety and Health Administration (OSHA): Birmingham, AL, September 20, 2000.
OSHA 2001a. Inspection Report for Marshfield Door Systems, Inc., Marshfield, WI; Inspection number 303864029; U.S. Department of Labor, Occupational Safety and Health Administration (OSHA): Madison, WI, November 9, 2001.
OSHA 2001b. Inspection Report for Newood Display Fixtures Manufacturing Company, Eugene, OR; Inspection number 304064835; Oregon Department of Consumer and Business Services, Oregon Occupational Safety and Health Division (OR-OSHA): Salem, OR, February 15, 2001.
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OSHA 2002b. Inspection Report for Parenti & Rafaelli, Ltd, Mount Prospect, IL; Inspection number 305228652; U.S. Department of Labor, Occupational Safety and Health Administration (OSHA): Des Plaines, IL, August 1, 2002.
OSHA 2003a. Inspection Report for Bushline, Inc., New Tazewell, TN; Inspection number 306132275; State of Tennessee, Department of Labor and Workforce Development, Division of Occupational Safety and Health: Nashville, TN, June 19, 2003.
OSHA 2003b. Inspection Report for Tru-Wood Cabinets, Inc., Ashland, AL; Inspection number 307013250; U.S. Department of Labor, Occupational Safety and Health Administration (OSHA): Birmingham, AL, December 5, 2003.
OSHA 2003c. Inspection Report for Simple Designs Manufacturing, Inc., Tualatin, OR; Inspection number 306629171; Oregon Department of Consumer and Business Services, Oregon Occupational Safety and Health Division (OR-OSHA): Salem, OR, October 21, 2003.
OSHA 2004a. Inspection Report for Armstrong Cabinets, Auburn, NE; Inspection number 306021239; U.S. Department of Labor, Occupational Safety and Health Administration (OSHA): Omaha, NE, September 30, 2004.
OSHA 2004b. Inspection Report for England, Inc., New Tazewell, TN; Inspection number 307674051; State of Tennessee, Department of Labor and Workforce Development, Division of Occupational Safety and Health: Nashville, TN, June 11, 2004.
OSHA 2004c. Inspection Report for Harris-Tarkett, Inc., Johnson City, TN; Inspection number 307206987; State of Tennessee, Department of Labor and Workforce Development, Division of Occupational Safety and Health: Nashville, TN, March 19, 2004.
OSHA 2005a. Inspection Report for Fiberesin Industries, Inc., Oconomowoc, WI; Inspection number 307061689; U.S. Department of Labor, Occupational Safety and Health Administration (OSHA): Milwaukee, WI, September 21, 2005.
OSHA 2005b. Inspection Report for Plymart, Inc., Boring, OR; Inspection number 308245372; Oregon Department of Consumer and Business Services, Oregon Occupational Safety and Health Division (OR-OSHA): Portland, OR, January 10, 2005.
OSHA 2005c. Inspection Report for The Gunlocke Company, LLC, Wayland, NY; Inspection number 307690578; U.S. Department of Labor, Occupational Safety and Health Administration (OSHA): North Syracuse, NY, September 21, 2005.
OSHA 2006a. Inspection Report for Wood Goods Industries, Inc., Luck, WI; Inspection number 307041707; U.S. Department of Labor, Occupational Safety and Health Administration (OSHA): Eau Claire, WI, December 18, 2006.
OSHA 2007a. Inspection Report for The Commercial Furniture Group, Morristown, TN; Inspection number 311144059; State of Tennessee, Department of Labor and Workforce Development, Division of Occupational Safety and Health: Nashville, TN, July 9, 2007.
OSHA 2008a. Inspection Report for Benvenuti and Stein, Inc., Evanston, IL; Inspection number 312188972; U.S. Department of Labor, Occupational Safety and Health Administration (OSHA): Des Plaines, IL, September 26, 2008.
OSHA 2008b. Occupational Safety and Health Standards: Toxic and Hazardous Substances: Formaldehyde; 29 C.F.R. 1910.1048 (December 12, 2008). http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10075 (accessed September 7, 2011).
OSHA 2008c. Inspection Report for Unilin Flooring NC, LLC, Mt. Gilead, NC; Inspection number 312479835; North Carolina Department of Labor, Division of Occupational Safety and Health: Charlotte, NC, July 28, 2008.
OSHA 2009a. Occupational Safety and Health Administration (OSHA) Integrated Management Information System (IMIS) database for formaldehyde (substance codes 1290, 1291, 1293) in all NAICS codes, encompassing the dates 1979 to 2009 (accessed June 2009).
OSHA 2009b. Inspection Report for Ameriwood Industries, Inc., Tiffin, OH; Inspection number 311606883; U.S. Department of Labor, Occupational Safety and Health Administration (OSHA): Toledo, OH, March 23, 2009.
OSHA 2010a. OSHA targets high hazard worksites for inspection. OSHA QuickTakes [Online] 2010, 9 (19). http://www.osha.gov/as/opa/quicktakes/qt10012010.html (accessed September 29, 2011).
OSHA 2010b. Chemical Sampling Information: Formaldehyde [Online]; Occupational Safety and Health Administration (OSHA): 2010. http://www.osha.gov/dts/chemicalsampling/data/CH_242600.html.
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Reinke 2009a. Reinke, Patricia H.; Keil, Charles B. Well-Mixed Box Model. In Mathematical Models for Estimating Occupational Exposure to Chemicals, 2nd ed.; Keil, Charles B.; Simmons, Catherine E.; Anthony, T. Renée, Eds.; American Industrial Hygiene Association: Fairfax, VA, 2009; pp 23-31.
RIOPA 2005a. Weisel, Clifford P.; Zhang, Junfeng (Jim); Turpin, Barbara J.; Morandi, Maria T.; Colome, Steven; Stock, Thomas H.; Spektor, Dalia M.; and Others. Relationships of Indoor, Outdoor, and Personal Air (RIOPA): Part I. Collective Methods and Descriptive Analyses; Number 130 Part I; Research Report for the Health Effects Institute (HEI): November 2005.

Tohmura 2000a. Tohmura, Shin-ichiro; Hse, Chung-Yun; Higuchi, Mitsuo. Formaldehyde emission and high-temperature stability of cured urea-formaldehyde resins. J. Wood Sci. 2000, 46, 303-309.
USDA 1996a. Ince, Peter J. Recycling of Wood and Paper Products in the United States; FPL-GTR-89; U.S. Department of Agriculture (USDA), Forest Service, Forest Products Laboratory: Madison, WI, 1996.
USEPA 1991a. Chemical Engineering Branch Manual for the Preparation of Engineering Assessments, Volume 1; U.S. Environmental Protection Agency (USEPA), Office of Pollution Prevention and Toxics, Chemical Engineering Branch: Washington, DC, February 1991.
USEPA 1996a. Turner, Sonji; Martin, Cybele; Hetes, Robert; Northeim, Coleen. Sources and Factors Affecting Indoor Emissions from Engineered Wood Products: Summary and Evaluation of Current Literature; EPA-600-R-96-067; U.S. Environmental Protection Agency (USEPA), National Risk Management Research Laboratory: Research Triangle Park, NC, June 1996.
USEPA 1997a. Exposures Factors Handbook; EPA/600/P-95/002; U.S. Environmental Protection Agency (USEPA), Office of Research and Development, National Center for Environmental Assessment: Washington, DC, August 1997.
USEPA 2000a. Case Studies: Low-VOC / HAP Wood Furniture Coatings; EPA-600/R-00-043; U.S. Environmental Protection Agency (USEPA), National Risk Management Research Laboratory: Research Triangle Park, NC, May 2000.
USEPA 2000b. Options for Revising CEB's Method for Screening-Level Estimates of Dermal Exposure  -  Final Report; U.S. Environmental Protection Agency (USEPA), Office of Pollution Prevention and Toxics, Chemical Engineering Branch: Washington, DC, June 2000.
USEPA 2009a. Risk Assessment Guidance for Superfund Volume I: Human Health Evaluation Manual (Part F, Supplemental Guidance for Inhalation Risk Assessment); U.S. Environmental Protection Agency (USEPA): January 2009.
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Appendix A
DEFINITION OF TERMS

Definition of Terms

American Conference of Governmental Industrial Hygienists (ACGIH)
ACGIH is a member-based organization of industrial hygienists whose goal is to advance occupational and environmental health.  ACGIH performs individual lab tests and develops with their own exposure limits that are sometimes used as suggested standards.
Action Level
Action level means a concentration designated in 29 CFR 1910 for a specific substance, calculated as an 8-hour time-weighted average (TWA), which initiates certain required activities such as exposure monitoring and medical surveillance.
CARB Compliant Products
In 2008, the California Air Resources Board (CARB) issued an airborne toxic control measure (ATCM) for three composite wood products.  The emission standards were issued in two phases.  Products that are manufactured in accordance with emissions standards issued under Phase 1 and Phase 2 of the CARB rule are referred to as CARB Phase 1 compliant and CARB Phase 2 compliant products, respectively.  Products that do not meet the standards set by CARB are herein referred to as non-CARB compliant products.  Table C-2 in Appendix C summarizes the CARB emission standards.
Ceiling Limit (C)
The air concentration for a substance that should not be exceeded during any part of the occupational exposure.
Composite Wood Products (CWPs)
The manufacture of most composite wood products involves an operation where the wood material is bonded with a resin. In this report, composite wood products refer specifically to hardwood plywood, medium-density fiberboard, and particleboard.
Composite Wood Product Fabrication
The manufacture of commercial or consumer products, such as cabinets and furniture, from HWPW, MDF, and PB.
Emission Level
A term used to indicate concentration of formaldehyde in a test chamber for a CWP.  In this report, emission levels are assumed to be measured using the ASTM E1333 large chamber test method.
Emission Rate
A term that is used in this document to describe the emissions of formaldehyde as a flux, meaning a quantity (such as mass) of formaldehyde emitted per unit emitting area and per unit time.  Concentrations measured using ASTM E1333 may be used to calculate emission rates (in units of flux) according to the method described in ASTM E1333 (see Appendix E).  Emission rates are alternatively referred to as emission factors (see the BIFMA M7.1-2007 method).
Exposure
Contact with a substance by inhalation, dermal contact, or ingestion.
The magnitude of exposure is a measure of the concentration of a substance contacted over a period of time.
Exposure Assessment
The process of determining how people come into contact with a hazardous substance, how often and for how long they are in contact with the substance, and how much of the substance they are in contact with.
Exposure Pathway
The route a substance takes from its source (where it began) to its end point (where it ends), and how people can come into contact with (or get exposed to) it. An exposure pathway has five parts: a source of contamination (such as a composite wood product); an environmental media and transport mechanism (such as the off-gassing of formaldehyde through air); a point of exposure (such as an individual's breathing zone); a route of exposure (inhalation), and a receptor population (people potentially or actually exposed). When all five parts are present, the exposure pathway is termed a completed exposure pathway.
Hardwood Plywood (HWPW)
According to FSCWPA, a hardwood or decorative panel that is:
	i. intended for interior use; and
	ii. composed of (as determined under the
	standard numbered ANSI/HPVA HP - 1 - 2009) an
	assembly of layers or plies of veneer, joined by an
	adhesive with:
		I. lumber core;
		II. particleboard core;
		III. medium-density fiberboard core;
		IV. hardboard core; or
		V. any other special core or special back 			material.

This does not include:
	i. military-specified plywood;
	ii. curved plywood; or
	iii. any other product specified in --
		I. the standard entitled `Voluntary Product
		Standard -- Structural Plywood' and 				numbered PS1 - 07; or
		II. the standard entitled `Voluntary Product
		Standard -- Performance Standard for Wood-			Based Structural-Use Panels' and numbered 			PS 2 - 04.
Note that the definition of hardwood plywood includes engineered veneer and any laminated product unless EPA exempts them by rule-making.
Laminated Product
According to FSCWPA, a product:

  (I) in which a wood veneer is affixed to:
   (aa) a particleboard platform;
   (bb) a medium-density fiberboard platform; or
   (cc) a veneer-core platform; and
  (II) that is:
   (aa) a component part;
   (bb) used in the construction or assembly of a finished good; and
   (cc) produced by the manufacturer or fabricator of the finished good in which the product is incorporated.

EPA has the discretion to change this definition.
Life Cycle
All stages of a product's development, from manufacture and processing to distribution, use, and disposal and recycling.
Manufacturing
The manufacture of the composite wood products: HWPW, MDF, and PB.  May also be referred to as "primary manufacturing".
Medium-Density Fiberboard (MDF)
According to FSCWPA, a panel composed of cellulosic fibers made by dry forming and pressing a resinated fiber mat (as determined under the standard numbered ANSI A208.2 - 2009).
No Added Formaldehyde (NAF) Resins
According to FSCWPA:
(A) IN GENERAL:
  (i) a  resin formulated with no added formaldehyde as part of the resin cross-linking structure in a composite wood product that meets the emission standards in subparagraph (C) as measured by: one test conducted pursuant to test method ASTM E - 1333 - 96 (2002) or, subject to clause (ii), ASTM D - 6007 - 02; and 3 months of routine quality control tests pursuant to ASTM D - 6007 - 02 or ASTM D - 5582 or such other routine quality control test methods as may be established by the Administrator through rulemaking.
  (ii) Test results obtained under clause (i)(I) or (II) by any test method other than ASTM E - 1333 - 96 (2002) must include a showing of equivalence by means established by the Administrator through rulemaking.

(B) INCLUSIONS: The term `no-added formaldehyde based resin' may include any resin made from:
  (i) soy;
  (ii) polyvinyl acetate; or
  (iii) methylene diisocyanate.

(C) EMISSION STANDARDS: The following are the emission standards for composite wood products made with no-added formaldehyde-based resins under this paragraph:
  (i) No higher than 0.04 parts per million of formaldehyde for 90 percent of the 3 months of routine quality control testing data required under subparagraph (A)(ii).
  (ii) No test result higher than 0.05 parts per million of formaldehyde for hardwood plywood and 0.06 parts per million for particleboard, medium-density fiberboard, and thin medium-density fiberboard.
National Institute for Occupational Safety and Health (NIOSH)
As part of the Centers for Disease Control, NIOSH is responsible for conducting research and making recommendations for the prevention of work-related illnesses and injuries.
Occupational Exposure
Contact with a substance as a result of one's work environment.
Occupational Safety and Health Administration (OSHA)
OSHA is the main federal agency charged with the enforcement of safety and health legislation. OSHA has the regulatory authority to set exposure limits for specific chemicals or groups of chemicals.
OSHA Integrated Management Information System (IMIS)
IMIS is an on-line data entry and information retrieval system designed to collect, process, retrieve, and communicate penalty assessment, arbitration, and collection information regarding OSHA's inspections.
OSHA Inspection Type:
FAT-CAT
Complaint

OSHA inspections following a fatality or catastrophe at a facility.
OSHA inspections resulting from worker complaints of unsafe or unhealthful working conditions.
Follow-Up
A follow-up inspection determines if the employer has corrected previously cited violations. If the employer fails to abate a former violation, he or she is subject to additional penalties until the violation is corrected.
Planned

Programmed

Related
The inspection was planned based on a particular reason, which can vary.  An example reason may include OSHA determining that a certain industry has a particular hazard more than others, so a random sample of facilities within that industry is selected for inspection.
Planned and/or programmed inspections aimed at specific high-hazard industries, workplaces, occupations, health substances, or other industries identified in OSHA's current inspection procedures.
The inspection was conducted due to concern over the facility regarding a different category, and upon investigation, OSHA determined that a related hazard should be monitored.

Referral

Unprogrammed
OSHA inspections resulting from referrals. Referrals may come from any source including but not limited to: state EPA, health department, fire department, building code inspectors, newspaper, and related OSHA inspections.
The facility was not inspected based on any planned or programmed list of industries or facilities.  These are the most random of OSHA inspections.
Particleboard (PB)
According to FSCWPA, a  panel composed of cellulosic material in the form of discrete particles (as distinguished from fibers, flakes, or strands) that are pressed together with resin (as determined under the standard numbered ANSI A208.1 - 2009)

This does not include any product specified in the standard entitled `Voluntary Product Standard -- Performance Standard for Wood-Based Structural-Use Panels' and numbered PS 2 - 04.
Peak Concentration
The maximum air concentration of a chemical that is observed for a given sampling event.
Permissible Exposure Limit (PEL)
PELs are regulatory limits issued by OSHA for the amount or concentration of a substance in the air. They may also contain a skin designation. OSHA PELs are based on an 8-hour time weighted average (TWA) exposure.
Potential Dose
The amount of a substance that is taken in by the body through ingestion, inhalation or dermal contact.  In this report, the potential dose, also referred to as "dose" applies to the amount of the substance that is inhaled.
Recommended Exposure Limit (REL)
Unless noted otherwise, RELs are time-weighted average (TWA) concentrations for up to a 10-hour workday during a 40-hour workweek. Unlike PELs, which are regulatory limits, RELs are recommended limits issued by NIOSH.
Short-Term Exposure Limit (STEL)
A STEL is defined as a 15-minute TWA exposure that should not be exceeded at any time during the work day even if the 8-hr TWA is within established limits. An averaging period other than 15 minutes may be used when this is warranted by observed biological effects.
The American Conference of Governmental Industrial Hygienists (ACGIH) recommends that exposures beyond the time-weighted average limit (whether regulatory or otherwise) up to the STEL should not occur more than 4 times per day with at least 60 minutes between successive exposures in this range.
Threshold Limit Value (TLV)
TLVs are recommended exposure limits that are issued by the ACGIH. TLVs are airborne concentrations of substances to which it is believed that nearly all workers may be repeatedly exposed day after day without adverse effect. There are three categories of TLVs: TLV-TWA; TLV-STEL; and TLV-C.
Time-Weighted Average (TWA) Concentration
Average air concentration of a substance based on a normal 8-hour work day and a 40-hour work week. OSHA PELs are based on an 8-hour time-weighted average (TWA) exposure.
Ultra Low-Emitting Formaldehyde (ULEF) Resin
According to FSCWPA:
(A) IN GENERAL:
  (i) The term `ultra low-emitting formaldehyde resin' means a resin in a composite wood product that meets the emission standards in subparagraph (C) as measured by:
   (I) 2 quarterly tests conducted pursuant to test method ASTM E - 1333 - 96 (2002) or, subject to clause (ii), ASTM D - 6007 - 02; and
   (II) 6 months of routine quality control tests pursuant to ASTM D - 6007 - 02 or ASTM D - 5582 or such other routine quality control test methods as may be established by the Administrator through rulemaking.
  (ii) Test results obtained under clause (i)(I) or (II) by any test method other than ASTM E - 1333 - 96 (2002) must include a showing of equivalence by means established by the Administrator through rulemaking.

(B) INCLUSIONS: The term `ultra low-emitting formaldehyde resin' may include:
  (i) melamine-urea-formaldehyde resin;
  (ii) phenol formaldehyde resin; and
  (iii) resorcinol formaldehyde resin.

(C) EMISSION STANDARDS:
  (i) The Administrator may, pursuant to regulations
issued under subsection (d), reduce the testing requirements for a manufacturer only if its product made with ultra low-emitting formaldehyde resin meets the following emission standards:
   (I) For hardwood plywood, no higher than 0.05 parts per million of formaldehyde.
   (II) For medium-density fiberboard:
     (aa) no higher than 0.06 parts per million of formaldehyde for 90 percent of 6 months of routine quality control testing data required under subparagraph (A)(ii); and
     (bb) no test result higher than 0.09 parts per million of formaldehyde.

   (III) For particleboard:
     (aa) no higher than 0.05 parts per million of formaldehyde for 90 percent of 6 months of routine quality control testing data required under subparagraph (A)(ii); and
     (bb) no test result higher than 0.08 parts per million of formaldehyde.
   (IV) For thin medium-density fiberboard:
     (aa) no higher than 0.08 parts per million of formaldehyde for 90 percent of 6 months of routine quality control testing data required under subparagraph (A)(ii); and
     (bb) no test result higher than 0.11 parts per million of formaldehyde.
  (ii) The Administrator may not, pursuant to regulations issued under subsection (d), exempt a manufacturer from third party certification requirements unless its product made with ultra low-emitting formaldehyde resin meets the following emission standards:
   (I) No higher than 0.04 parts per million of formaldehyde for 90 percent of 6 months of routine quality control testing data required under subparagraph (A)(ii).
   (II) No test result higher than 0.05 parts per million of formaldehyde for hardwood plywood and 0.06 parts per million for particleboard, medium-density fiberboard, and thin medium-density fiberboard.

Appendix B
DATA QUALITY ACCEPTANCE CRITERIA SPECIFICATIONS

                Data Quality Acceptance Criteria Specifications

                       Specifications for Data Elements
                            Acceptance Criterion:
                            Description/Definition
                                 Specification

Currency
Is the information up to date?  Does it reflect current conditions?
Process Description: Year of source is 1990 or after

Number of Sites and Production Data: Year of source is 2000 or after and correlates with number of sites

Exposure Data:
Priority - Year of source is 2004 or after[1] Consider -  Year of source is 1999 or after

Geographic Scope
Does the information reported reflect an area relevant to the assessment?
All Data:
Priority  -  sources describing U.S. sites

When U.S. data are not available, consider sources from countries with geographic proximity that may adopt similar processes or from other developed countries that may have similar regulations and standards.

Process Description:
Consider  -  sources describing Canadian, Mexican, or European processes.

Number of Sites and Production Data:
Consider  -  North American sites  (and interpolate to estimate U.S. sites and production)

Exposure Data:
Consider  -  Canadian or European data.

Accuracy/Reliability
Is the information or data from a peer-reviewed, government, or industry-specific source? Is the source published? Is the author engaged in a relevant field such that competent knowledge is expected (i.e., the author writes for an industry trade association publication versus a general newspaper)?
All Data:
U.S. or other government publication

For an academic researcher:
   * Publication in peer-reviewed journal
   * Presentation at a technical conference
   * Source has documented qualifications/ credentials to discuss particular topic

For an industry expert or trade group:
   * Presentation at a technical conference where the information is subject to review by other industry experts
   * Source has documented qualifications/ credentials to discuss particular topic
   * Source represents a large portion of the industry of interest
Unbiased[2]
Is the information objective towards a particular product or outcome?
All Data:
   * Objective of the information is clear.
   * Methodology is designed to answer a specific question.

Comparability
Are the data comparable to other sources that have been identified or are they significantly different than other sources?
Production Data, Exposure Data, and Number of Sites:  Values are within the same order of magnitude of each other.

Process Description: Matches or is similar to other information for the same industry and will be evaluated on a case-by-case basis.

Representativeness
Do the data reflect typical industry practices?
All Data:
Information is relevant to the industry and from a reputable source with qualifications in the industry of interest.

Data are based on a large industry survey or study, as opposed to a case study or sample from a limited number of sites.
Applicability
For surrogate data, are the data expected to be similar for the industry of interest?
Surrogate data  used to fill data gaps must be judged to be similar to the data of interest:
   * Industry is similar in size
   * Same types of chemicals are used
   * Similar processes and activities are performed
   * Similar levels of engineering controls and personal protective equipment are used

1 EPA promulgated in 2004 the Plywood and Composite Wood Products MACT Rule for hazardous air pollutants (HAPs), including formaldehyde, for regulated units.
[2] Information from advocacy groups should be collected and judged for acceptability.  While such information may be biased, it may provide references to other useful sources.
Appendix C
EXISTING FORMALDEHYDE OCCUPATIONAL EXPOSURE LIMITS AND FORMALDEHYDE OFF-GASSING EMISSION STANDARDS FOR COMPOSITE WOOD PRODUCTS

Formaldehyde Occupational Exposure Limits

The Occupational Safety and Health Administration (OSHA) sets permissible exposure limits (PELs) to regulate worker exposure to formaldehyde in occupational settings.  OSHA has established two types of exposure limits for airborne exposures to formaldehyde: a 0.75 parts per million (ppm) time-weighted average (TWA) PEL over an 8-hour period and a 2 ppm short-term exposure limit (STEL) over a 15-minute period.
Table C-1 summarizes these OSHA exposure limits as well as other formaldehyde exposure limits for the U.S. and for other countries.
Table C-1. Existing Occupational Exposure Limits for Formaldehyde
                                    Country
                              Concentration (ppm)
                                     Type
USA-ACGIH
                                      0.3
                                    Ceiling
USA-NIOSH
                                     0.016
                                      TWA
USA-OSHA[b]
                                     0.75
                                      TWA
USA-OSHA
                                      2.0
                                     STEL
Canada-Alberta
                                      2.0
                                    Ceiling
Canada-Ontario
                                      0.3
                                    Ceiling
Canada-Quebec
                                      2.0
                                    Ceiling
Sweden
                                      0.5
                                      TWA
New Zealand
                                      1.0
                                    Ceiling
Australia [a]
                                      1.0
                                      TWA
Japan
                                      0.5
                                      TWA
United Kingdom
                                      2.0
                                      TWA
a  -  Australia proposed a lower occupational exposure limit of 0.3 ppm in 2008 (Chimar Hellas undated).
b  -  The OSHA action level for formaldehyde is 0.5 ppm TWA (29 CFR § 1910.1048).
Sources: IARC 2006a, Chimar Hellas undated, and OSHA 2010b

Formaldehyde Emission Standards for Composite Wood Products

Emission standards have been established in the U.S. for HWPW, MDF, and PB.  The American National Standards Institute (ANSI) established a voluntary standard for MDF and PB, while the Department of Housing and Urban Development (HUD) established national standards for plywood and particleboard (CARB 2007a).  In 2008, CARB issued an air toxics control measure (ATCM) for the state of California, which provided stricter formaldehyde emission standards than the existing national standards (see Table C-2).  The ANSI standards have been revised to reflect the CARB ATCM emission standards.
The CARB regulation focuses only on three types of composite wood products: HWPW, PB, and MDF.  CARB set emission standards for each of these products based on best achievable control technologies (BACTs).  The BACTs were selected based on CARB survey results, information in the open literature, and expert judgment on low- and no-added formaldehyde resin technologies.  The selected BACTs are such that the three regulated products have different emission standards (CARB 2007a).
CARB reported the resin types used by the manufacturers who responded to the CARB 2003 survey (CARB 2007a).
Of the HWPW manufacturer responses, which accounted for 73% of domestic HWPW production:
               o All companies reported using ammonia-UF resin.  The lowest emission rates were achieved with the use of catalysts, such as ammonium chloride or hexamethylenetetramine.
         * Of the PB manufacturer responses, which accounted for 53% of domestic PB production:
               o 51% of the reported production volume used a straight polymer UF resin;
               o 48% of the reported production volume used a methanol-UF resin; and
               o 1% of the reported production volume used a blended PF-UF resin.
         * Of the MDF manufacturer responses, which represented 83% of domestic MDF production:
               o 40% of the reported production volume used a straight polymer UF resin;
               o 20% of the reported production volume used a methanol-UF resin;
               o 39% of the reported production volume used a melamine-UF resin with sodium chloride catalyst; and
               o 1% of the reported production volume used MDI resin.

The majority of the reported resins used were UF resins with many using additives, such as ammonia or methanol, and catalysts.

Table C-2. California Phase 1 and Phase 2 Formaldehyde Emission Standards

                 ASTM E1333 Standard Concentrations (ppm) [a]
                    Phase 1 Formaldehyde Emission Standards
                                Effective Date
                                  HWPW-VC [b]
                                  HWPW-CC [c]
                                      PB
                                      MDF
                                   tMDF [d]
                                   Jan 2009
                                     0.08
                                       --
                                     0.18
                                     0.21
                                     0.21
                                   July 2009