Human Exposure February 18, 2004 Risk Assessment Science Support Branch U. S. Environmental Protection Agency Office of Pesticide Programs Antimicrobials Division 2 TABLE OF CONTENTS 1.0 EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.0 OCCUPATIONAL EXPOSURE AND RISK ASSESSMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 A. Toxicological Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 ( 1) Criteria for Conducting Exposure Assessments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 ( 2) Summary of Toxicity Concerns Relating to Occupational Exposures . . . . . . . . . . . . . . . . . . . . . . . . . . 10 ( a) Acute Toxicology Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 ( b) Summary of Toxicological Endpoint Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 ( c) Dermal Absorption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 B. Occupational Exposures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 ( 1) Handler Exposures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 ( a) Occupational Handlers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 ( 2) Handler Exposure Data and Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 ( a) Handler Exposure Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 ( b) Chemical Specific Handler Exposure Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 ( 3) Handler Risk Assessment and Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 ( a) Handler Exposure and Non Cancer Risk Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 ( b) Handler Exposure and Cancer Risk Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 ( c) Occupational Handler Scenarios with Non Cancer Dermal Risk Concerns . . . . . . . . . . . . . . . . 34 ( d) Occupational Handler Scenarios with Non Cancer Inhalation Risk Concerns . . . . . . . . . . . . . . 35 ( e) Occupational Handler Scenarios with Cancer Risk Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . 35 ( 4) Postapplication Exposures and Risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 ( a) Occupational Postapplication Exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 ( 5) Occupational Postapplication Data, Assumptions, Exposure, and Risk Calculations . . . . . . . . . . . . . . . 37 ( a) Postapplication Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 ( b) Short, Intermediate, and Long Term Inhalation Exposure and Non Cancer Risks . . . . . . . . . 39 ( c) Short, Intermediate, and Long Term Dermal Exposure and Non Cancer Risk Calculations . . 42 ( d) Postapplication Exposure Cancer Risk Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 ( 6) Occupational Postapplication Risk Assessment and Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . 43 ( a) Postapplication Non Cancer Risks from Dermal Exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 ( b) Postapplication Non Cancer Risks from Inhalation Exposure . . . . . . . . . . . . . . . . . . . . . . . . . 43 ( c) Postapplication Dermal and Inhalation Scenarios with Cancer Risks . . . . . . . . . . . . . . . . . . . 44 ( 7) Data Gaps, Uncertainties, and Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 ( 8) Results Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 3 3.0 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 1.0 EXECUTIVE SUMMARY Background Wood preservative pesticides containing inorganic arsenicals and/ or chromium compounds are registered as technical source/ manufacturing use products or industrial end use product concentrates to formulate Chromated Copper Arsenate ( CCA), Ammoniacal Copper Zinc Arsenate ( ACZA), Ammoniacal Copper Arsenate ( ACA) and Acid Copper Chromate ( ACC) aqueous treatment solutions for pressure treatment applications.

Waterborne wood preservatives containing arsenic and/ or chromium in a mixture with copper are predominantly formulated as Chromated Copper Arsenate or CCA. Formulated wood preservative products containing arsenic and/ or chromium compounds have been registered since the 1940' s when pesticides were under the regulatory purview of the United States Department of Agriculture ( USDA), and since its' inception in the 1970' s, regulated under FIFRA with the U. S. EPA.

Presently, products are registered for pressure treatment of wood intended for above ground and ground contact, as well as in fresh water and marine environments. Wood treated with these preservatives are specified for commercial, institutional, and limited residential/ farm construction uses in indoor and outdoor sites.

All products are Restricted Use Pesticides: technical grade/ manufacturing use products ( MUP's)

containing sources of either Arsenic acid ( 2) or Chromic acid ( 5); and 16 are industrial end use products ( EUP's)

as either separate chemical sources of arsenic ( 3) or chromium ( 1), or as chemical mixtures of CCA ( 11) or ACC ( 1). ( Refer to the Case Overview section of this RED for a complete profile of all pesticide active ingredients and product formulations/ use patterns covered under Reregistration Case 0132).

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All non pressure treatments have been voluntarily cancelled by the registrants. The cancellation letter dated May 28, 2003 removed all non pressure treatment arsenical products from the market: EPA Reg. Nos.

3008 21, 75341 1 ( formerly 3008 8), and 75341 7 ( formerly 3008 68). There remain no other arsenical 4 products that were registered for non pressure treatments. The ACC label ( EPA Reg. No 3008 60) specifically states " For Pressure Plant Use Only". The labeling for component products used to make ACZA ( Parts A, B,

C Reg. Nos. 3098 16,  17,  18, respectively) also states intended use for pressure treated wood products.

Scope of Occupational Assessment for Wood Preservatives Containing Arsenic and/ or Chromium Presented herein is the " occupational" exposure and risk assessment for industrial workers involved in pressure treatment applications to wood using preservatives containing inorganic arsenicals and/ or chromium compounds. The scope of EPA registered preservative chemicals grouped under the term " inorganic arsenicals and/ or chromium compounds" includes:

° Separate chromium ( Cr) and arsenic ( As) technical source, manufacturing use products registered with the Agency for use in formulating arsenical and/ or chromated preservative mixtures for wood pressuretreatment and ° Registered industrial end use product concentrates containing sources of Cr or As, or mixtures of CCA or ACC, intended for dilution with water to create treatment solutions for wood pressure treatment applications.

Note that certain registered arsenical and/ or chromated preservative products are mixtures of several active ingredients. Some active ingredients in these product mixtures are not covered under this RED for Wood Preservatives Containing Arsenic and/ or Chromium, but have been or will be assessed for reregistration eligibility under separate RED cases. The predominant inorganic arsenical preservatives used by the wood treatment industry are mixtures of " chromated copper arsenate" or more commonly referred to as " CCA". CCA preservatives will therefore be the focus of the Agency's human health assessment in this RED, and be the basis for conducting the occupational exposure and risk assessment Other registered wood preservatives containing sources of copper in combination with either chromium or arsenic compounds include: acid copper chromate ( ACC), ammoniacal copper arsenate ( ACA), and ammoniacal copper zinc arsenate ( ACZA).

These preservatives are used for specialized applications or in cases where wood penetration by CCA chemicals can not be achieved ( e. g., ACC used for cooling tower applications, ACA and ACZA used on large dimension wood products made from hard to treat wood species such as Douglas Fir).

Cupric Oxide, the form of copper used in CCA treatment solutions, is not included as an active ingredient covered under this RED. Reregistration requirements for Cupric Oxide will be addressed separately in a RED document for Copper, and oxides, Case Number 4025, slated to be issued at a future date. Also, Zinc Oxide, the 5 zinc component of ACZA, has already been assessed by the Agency for the wood preservative use patterns under the Zinc Salts RED, Case Number 4099, dated August, 1992.

Occupational Exposures to Arsenical and/ or Chromated Wood Preservatives The Occupational Exposure Chapter of the Wood Preservatives Containing Arsenic and/ or Chromium Re registration Eligibility Decision Document ( RED) addresses potential exposures and risks of chromium ( Cr)

and arsenic ( As) to humans who may be exposed to Chromated Copper Arsenate ( CCA) and related arsenicals and chromated wood preservatives in " occupational settings" as: ( 1) handlers ( mixers, loaders, applicators) of CCA and related pesticide products; and ( 2) individuals who are exposed to CCA and related pesticides through postapplication or reentry activities. The chromium assessed is hexavalent. The trivalent chromium is not of toxicological significance. Hexavalent chromium is assessed using the exposures monitored in the pressure treatment exposure study for chromium VI coupled with the toxicological endpoints for chromium VI.

The occupational settings are characterized as wood treatment plants where Southern Yellow Pine dimensional lumber is pressure treated. Therefore representative occupational handler exposure scenarios were developed for treatment plant workers only.

Potential postapplication exposures may occur in occupational settings such as wood pressure treatment plants where treated lumber is handled for QA/ QC testing, or storage/ transport, or in commercial, institutional,

and residential outdoor settings where the wood is fabricated into structures and professionally installed.

Occupational postapplication exposure scenarios were developed for treatment plant workers only, since it is anticipated that handling freshly treated wood and performing postapplication work tasks in treatment areas constitutes postapplication scenarios with the potential for maximum exposures. 6 The pressure treatment exposure scenarios developed for this RED Chapter are representative of potential occupational exposures to inorganic arsenical preservatives over short term ( 1 day to 1 month),

intermediate term ( 1 6 months), and long term ( > 6 months) exposure durations.

Occupational Handlers Non cancer and cancer dermal and inhalation exposures were assessed separately for arsenic and chromium VI for pressure treatment scenarios. The Margins of Exposure ( MOEs) for all occupational handler scenarios evaluated are presented in Table 15 of this report.

Dermal Exposure: Non Cancer Arsenic: All the scenarios that exceed the Agency's level of concern for dermal non cancer exposure for arsenic are presented below. The Agency's level of concern for arsenic from dermal exposure is as follows:

short term and intermediate term ( MOEs < 30) and long term ( MOEs < 3).

Short Term and Intermediate Term ° Applying Liquid Formulations at Pressure Treatment Plants Using an Automatic/ Closed Delivery System ( Opening and Closing the Retort) [ treatment operator ( TO)] ( MOE of concern; MOE =

16);

Long Term ° Applying Liquid Formulations at Pressure Treatment Plants Using an Automatic/ Closed Delivery System ( Opening and Closing the Retort) [ treatment operator ( TO) and treatment assistant ( TA)] ( MOE of concern; MOEs = 0.3 for TO, and 0.8 for TA);

Chromium VI: Since dermal irritation and dermal sensitization are the primary exposure concerns through the dermal route, no toxicological endpoint was selected for use in assessing dermal exposure risks to chromium VI. Risk mitigation will continue to be addressed through appropriate precautionary labeling statements.

Inhalation Exposure: Non Cancer 7 Arsenic: The MOE's for the inhalation exposure scenarios presented in the risk assessment do not exceed the Agency's level of concern for short, intermediate, and long term exposures to arsenic. 8 Chromium VI: The MOE's for the inhalation exposure scenarios that exceed the Agency's level of concern ( i. e. MOEs < 100) for short term, intermediate term, and long term inhalation exposures to chromium VI are presented below. Trivalent chromium is not of toxicological significance and is therefore not assessed. Chromium VI risks are based on the registrant's exposure study for pressure treatment workers ( note: all inhalation samples were non detect and ½ LOD was used in assessing the risks).

Short Term, Intermediate Term, and Long Term ° Applying Liquid Formulations at Pressure Treatment Plants Using an Automatic/ Closed Delivery System ( Opening and Closing the Retort) [ treatment operator ( TO) and treatment assistant ( TA)] ( MOEs of concern, MOEs = 7 for TO and TA based on ½ LOD);

Dermal and Inhalation Exposure: Cancer Carcinogenic endpoints related to lifetime dermal and inhalation exposures to arsenic, and inhalation exposure to chromium VI have been identified. In general, the Agency is concerned when occupational cancer risk estimates exceed 1 x 10 4 ( E 4) . The Agency will seek ways to mitigate the risks, to the extent that it is practical and economically feasible, to lower the risks to 1 x 10 6 ( E 6) or less. The following handler scenarios have cancer risks between 1 x 10 5 ( E 5) and 1 x 10 2 ( E 2) at the assessed level of mitigation. Cancer risks for each scenario are presented in Table 16.

Arsenic:

Lifetime Dermal Cancer Risk ( > E 4 )

° Applying Liquid Formulations at Pressure Treatment Plants Using an Automatic/ Closed Delivery System ( Opening and Closing the Retort) [ treatment operator ( TO) and treatment assistant ( TA)] ( risks of concern = 4.1E 3 for TO, and 1.4E 3 for TA ); and Lifetime Inhalation Cancer Risk ( > E 4 )

° Applying Liquid Formulations at Pressure Treatment Plants Using an Automatic/ Closed Delivery System ( Opening and Closing the Retort) [ treatment operator ( TO) and treatment assistant ( TA)] ( risks of concern = 2.0E 4 for TO, and 1.2E 4 for TA); and Chromium VI:

Lifetime Inhalation Cancer Risk ( > E 4 )

° Applying Liquid Formulations at Pressure Treatment Plants Using an Automatic/ Closed Delivery System ( Opening and Closing the Retort) [ treatment operator ( TO) and treatment assistant ( TA)] ( risks of concern using ½ LOD as all samples were non detect= 1.7E 4 for TO, and 1.6E 4 for TA); and 9 Occupational Postapplication Exposure Non cancer and cancer dermal and inhalation postapplication exposures were assessed separately for arsenic and chromium VI for pressure treatment scenarios. Wood treatment plant postapplication job functions as per the ACC worker exposure study ( MRID 455021 01) were relied upon to develop the postapplication scenarios. The Margins of Exposure ( MOEs) for all occupational postapplication scenarios evaluated are presented in Table 21 of this report.

Dermal Exposure: Non Cancer Arsenic: Acute, subchronic, and chronic toxicity endpoints related to dermal exposures to arsenic have been identified. The Agency's level of concern for arsenic from dermal exposure is as follows: short term and intermediate term ( MOEs < 30) and long term ( MOEs < 3). All the scenarios that exceed the Agency's level of concern for dermal non cancer exposure for arsenic are presented below.

Short Term and Intermediate Term ° Loader Operator ( MOE of concern, MOEs = 21); ° Tram Setter ( MOE of concern, MOEs = 8); ° Supervisor ( MOE of concern, MOEs = 16); ° Tally Man ( MOE of concern, MOEs = 18); and, ° Test Borer ( MOE of concern, MOEs= 27).

Long Term ° Loader Operator ( MOE of concern, MOE = 0.3); ° Test Borer ( MOE of concern, MOE = 4); ° Tram Setter ( MOE of concern, MOE = 0.1); ° Supervisor ( MOE of concern, MOE = 0.3); ° Tally Man ( MOE of concern, MOE = 0.3); and, ° Stacker Operator ( MOE of concern, MOE = 0.6).

Chromium VI: Since dermal irritation and dermal sensitization are the primary exposure concerns through the dermal route, no toxicological endpoint was selected for use in assessing dermal postapplication exposure risks to chromium VI. Risk mitigation will continue to be addressed through appropriate precautionary labeling statements.

Inhalation Exposure: Non Cancer Arsenic: Acute, sub chronic, and chronic toxicity endpoints related to inhalation exposures to arsenic have been identified. The Agency's level of concern for arsenic from inhalation exposure is as follows: shortterm and intermediate term ( MOEs < 100) and long term ( MOEs < 3). The MOEs for the inhalation exposure scenarios presented in the risk assessment do not exceed the Agency's level of concern. 10 Chromium VI: The MOEs for the inhalation exposure scenarios presented in the risk assessment exceed the Agency's level of concern for short term, intermediate term, and long term inhalation exposures to chromium VI ( i. e., MOEs < 100) based on the toxicological information for Chromium ( VI). Even though all inhalation samples were below the detection limit, inhalation MOEs are exceeded for all postapplication exposure scenarios as follows:

Short Term, Intermediate Term, and Long Term ° Loader Operator ( MOE of concern, MOE = 6); ° Test Borer ( scenario not assessed for chromium); ° Tram Setter ( MOE of concern, MOE = 6); ° Supervisor ( MOE of concern, MOE = 6); ° Tally Man ( scenario not assessed for chromium); and, ° Stacker Operator ( MOE of concern, MOE = 6).

Dermal and Inhalation Exposure: Cancer Carcinogenic endpoints related to lifetime dermal and inhalation exposures to arsenic, and inhalation exposure to chromium VI have been identified. In general, the Agency is concerned when occupational cancer risk estimates exceed 1 x 10 4 ( E 4) . The Agency will seek ways to mitigate the risks, to the extent that it is practical and economically feasible, to lower the risks to 1 x 10 6 ( E 6) or less. The following worker scenarios have cancer risks between 1 x 10 5 ( E 5) and 1 x 10 2 ( E 2) at the assessed level of mitigation. Occupational postapplication cancer risks for each scenario are presented in Table 21.

Arsenic:

Lifetime Dermal Cancer Risk ( > E 4 )

° Loader Operator ( risk of concern = 3.3E 3 ); ° Test Borer ( risk of concern = 2.5E 4); ° Tram Setter ( risk of concern = 8.4E 3); ° Supervisor ( risk of concern = 4.1E 3); ° Tally Man ( risk of concern = 3.8E 3); and, ° Stacker Operator ( risk of concern = 1.8E 3). 11 Lifetime Inhalation Cancer Risk ( > E 4 )

° Loader Operator ( risk of concern = 1.6E 4 ); ° Test Borer ( risk of concern = 6.3E 5 ); ° Tram Setter ( risk of concern = 4.7E 4); ° Supervisor ( risk of concern = 2.8E 4); ° Tally Man ( risk of concern = 8.0E 5); and, ° Stacker Operator ( risk of concern = 6.0E 5).

Chromium VI:

Lifetime Inhalation Cancer Risk ( > E 4 )

° Loader Operator ( risk of concern = 2.0E 4 ); ° Test Borer ( scenario not assessed for chromium ); ° Tram Setter ( risk of concern = 2.0E 4); ° Supervisor ( risk of concern= 2.1E 4). ° Tally Man ( scenario not assessed for chromium); and, ° Stacker Operator ( risk of concern = 1.6E 4).

Occupational Risk Characterization Summary The exposure and risk assessment conducted for occupational populations involved with pressure treatments using inorganic arsenicals indicated the following:

° Occupational handlers of registered inorganic arsenical pesticides for pressure treatments are best protected under conditions where appropriate dermal and inhalation personal protective equipment ( PPE) is worn.

° Handler exposure estimates based on chemical specific monitoring data collected for pressure treatment workers indicate that additional risk mitigation is warranted especially for individuals directly involved with work tasks requiring contact with the treatment cylinder/ retort ( i. e., treatment operator/ treatment assistant).

° Postapplication exposures are a concern for industrial workers in wood pressure treatment plants across most all postapplication scenarios assessed ( dermal exposure concerns for arsenic and inhalation concerns for chromium VI) based on chemical specific monitoring data collected for pressure treatment workers. Additional risk mitigation is warranted during postapplication work tasks involving contact with treatment equipment and treated wood.

° The risks presented for hexavalent chromium are based on inhalation samples that were all non detect. The risks are estimated using ½ the limit of detection ( LOD). A lower detection limit is needed based on the sensitivity of the toxicological endpoints for chromium VI. 12 2.0 OCCUPATIONAL EXPOSURE AND RISK ASSESSMENT A. Toxicological Considerations ( 1) Criteria for Conducting Exposure Assessments An occupational exposure and risk assessment is required for an active ingredient if ( 1) certain toxicological criteria are triggered and ( 2) there is potential exposure to handlers ( e. g., mixers, loaders, applicators, etc.) during pesticide product use, or during postapplication: to persons entering treated sites after application is complete, or when exposures are anticipated from handling pesticide treated articles. For the Inorganic Arsenical Wood Preservatives containing arsenic and chromium as active ingredients, both criteria are met.

( 2) Summary of Toxicity Concerns Relating to Occupational Exposures ( a) Acute Toxicology Categories The toxicological data base for the arsenic and chromium compounds found in inorganic arsenicals is adequate and will support re registration eligibility for CCA and related wood preservative pesticides. Toxicity categories for Arsenic ( V) are shown in Table 1a. Toxicity categories for Chromium ( VI) are shown in Table 1b. Tables 1a and 1b summarize these toxicity findings of OPP's HIARC Reports ( U. S. EPA, 2002). 13 Table 1a. Acute Toxicity Summary of Arsenic Acid ( 75%)

Guideline Reference No. Study Type MRID/ Data Accession No. Results Toxicity Category 81 1 ( OPPTS 870.1100) Acute Oral 404090 01 Mouse LD50 =

141 mg/ kg =  160 mg/ kg M+ F = 150 mg/ kg II 26356 Rat LD50 =

76 mg/ kg =  37 mg/ kg M+ F = 52 mg/ kg I 81 2 ( OPPTS 870.1200) Acute Dermal 26356 Rabbit LD50 =

1750 mg/ kg =  2300 mg/ kg II 81 3 ( OPPTS 870.1300) Acute Inhalation 404639 02 Mouse LC50 =

1.153 mg/ L =  0.79 mg/ L M+ F = 1.040 mg/ L II 81 4 ( OPPTS 870.2400) Primary Eye Irritation 26356 Rabbit 3/ 6 animals died by day 7. The 3 surviving animals were sacrificed on day 9 because of severe ocular irritation and corrosion. I 81 5 ( OPPTS 870.2500) Primary Skin Irritation 26356 Rabbit At 30 minutes, all animals showed moderate to severe erythema and slight to severe edema. All animals died prior to the 24 hour observation. I 81 6 ( OPPTS 870.2600) Dermal Sensitization 406462 01 Guinea Pig Not a Sensitizer 14 Table 1b. Acute Toxicity Summary of Cr( VI)

Guideline Reference No. Study Type [ Substance] MRID/ Literature Results Toxicity Category 81 1 ( OPPTS 870.1100) Acute Oral/ Rat [ Chromic Acid, 100% a. i.] 434294 01 LD50 =

56 mg/ kg =  48 mg/ kg M+ F = 52 mg/ kg I 81 2 ( OPPTS 870.1200) Acute Dermal/ Rabbit [ Chromic Acid, 100% a. i.] 434294 02 LD50 =

> 48 mg/ kg =  48 mg/ kg M+ F = 57 mg/ kg I 81 3 ( OPPTS 870.1300) Acute Inhalation/ Rat [ Chromic Acid, 100% a. i.] 434294 03 LC50 =

0.263 mg/ L =  0.167 mg/ L M+ F = 0.217 mg/ L I 81 4 ( OPPTS 870.2400) Primary Eye Irritation [ Various Cr( VI) compounds] Literature Waiver Corrosive I 81 5 ( OPPTS 870.2500) Primary Dermal Irritation [ Various Cr( VI) compounds] Literature Waiver Corrosive I 81 6 ( OPPTS 870.2600) Dermal Sensitization / Guinea Pig [ Various Cr( VI) compounds] Literature Strong sensitizer ( b) Summary of Toxicological Endpoint Selection The OPP Hazard Identification Assessment Review Committee ( HIARC) reports for Arsenic and Chromium, both dated April 15, 2002, indicate that there are toxicological endpoints of concern for arsenic as As ( V) and chromium as Cr ( VI) ( U. S. EPA, 2002). Dermal and inhalation endpoints of concern have been identified for characterizing short term, intermediate term, and long term exposures for arsenic and chromium VI. 15 Arsenic The lowest observed adverse effect level ( LOAEL) selected for short and intermediate term dermal exposures for arsenic ( 0.05 mg/ kg/ day) is based on toxic effects including edema of the face; gastrointestinal, upper respiratory, skin, peripheral and neuropathy symptoms. The LOAEL comes from the work of Franzblau et al. ( 1989) and Mizuta et al. ( 1956) who examined oral exposure to individuals exposed during a reported poisoning incident involving the presence of arsenic [ probably calcium arsenate] contained in soy sauce. The NOAEL ( 0.0008 mg/ kg/ day) selected for long term dermal exposures for arsenic was based on toxic effects from an oral epidemiology study performed by Tseng et al. ( 1968) and Tseng ( 1977). Each endpoint was established using an oral toxicity study. Therefore, for purposes of the risk assessment, a dermal absorption factor of 6.4 percent may be needed to correct the oral dose to a dermal dose. For short, intermediate and long term endpoints, the body weight of an adult male ( 70 kg) was used to assess intermediate and long term dermal handler and postapplication risks. The HIARC report recommended a margin of exposure ( MOE) of 30 for the short and intermediate term dermal risk ( 10x intraspecies variation and 3x for the use of the LOAEL), and an MOE of 3 for the long term dermal risk ( Table 2a) ( 3x rather than 10x because of the large sample size (> 40,000)).

Short, intermediate, and long term endpoints were not identified in the HIARC report for inhalation exposures to arsenic. Since no inhalation studies are available, committee selected the same studies and uncertainty factors as for the dermal risk assessments. Since the dose identified for inhalation risk assessments are from oral studies, route to route extrapolation should be as follows:

Step I: The inhalation exposure component ( i. e., µ g a. i./ day) using a 100% ( default) absorption rate and application rate should be converted to an equivalent oral dose ( mg/ kg/ day);

Step II: The dermal exposure component ( i. e., mg/ kg/ day) using 6.4 % absorption factor and application rate should be converted to an equivalent oral dose. The dose should be combined with the converted oral dose in Step I.

Step III: To calculate the MOE's, the combined dose from Step I and II should then be compared to the oral LOAEL of 0.05 mg/ kg/ day for short and intermediate term exposure and the oral NOAEL of 0.0008 mg/ kg/ day for long term exposure.

The cancer endpoint from oral exposure is classified as group A ( known human carcinogen) with a cancer slope factor of 3.67 ( mg/ kg/ day) 1 ( Table 2a). The inhalation unit risk ( IUR) for a continuous 24 hour exposure is 4.3 x 10 3 (

g/ m3) 1 which is equivalent to a cancer slope factor of 15.1 ( mg/ kg/ day) 1 for the general population. To assess inhalation cancer risks from an 8 hour work day, the 24 hour derived CSF is adjusted to an 8 hour exposure representing a typical work day ( i. e., 24 hour CSF x ( 8 hr/ 24 hr)). 16 Table 2a. Toxicological Endpoints for Assessing Occupational Exposures/ Risks to Arsenic ( V)

EXPOSURE SCENARIO DOSE ( mg/ kg/ day) ENDPOINT STUDY Acute Dietary This risk assessment is not required.

Chronic Dietary This risk assessment is not required.

Incidental Short and Intermediate Term Oral LOAEL= 0.05 MOE = 30 Based on edema of the face, gastrointestinal, upper respiratory, skin, peripheral and neuropathy symptoms Franzblau et al.( 1989) and Mizuta et al. ( 1956)

Dermal Short and Intermediate Term ( a) ( b) LOAEL= 0.05 MOE = 30 Based on edema of the face, gastrointestinal, upper respiratory, skin, peripheral and neuropathy symptoms Franzblau et al.( 1989) and Mizuta et al. ( 1956)

Dermal Long Term ( a) ( b) NOAEL= 0.0008 MOE = 3 Based on hyperpigmentation, keratosis and possible vascular complications. Tseng et al. ( 1968) and Tseng ( 1977)

Inhalation Short and Intermediate Term( c) LOAEL= 0.05 MOE = 30 Based on edema of the face, gastrointestinal, upper respiratory, skin, peripheral and neuropathy symptoms Franzblau et al.( 1989) and Mizuta et al. ( 1956)

Inhalation, Long Term NOAEL= 0.0008 MOE = 3 Based on hyperpigmentation, keratosis and possible vascular complications. Tseng et al. ( 1968) and Tseng ( 1977)

Carcinogenicity  Inhalation ( Inhalation Risk) CSF= 15.1 ( d) ( mg/ kg/ day) 1 ( For general Population) Lung cancer Chronic epidemiological inhalation study on humans CSF= 5.0 ( e) ( mg/ kg/ day) 1 ( For 8 hour working day)

Carcinogenicity  Oral Ingestion ( Oral and Dermal Risks) CSF = 3.67 ( f) ( mg/ kg/ day) 1 Internal organ cancer ( liver, kidney, lung and bladder) and skin cancer Chronic epidemiological oral study on humans Note: ( a). MOE = Margin of Exposure; NOAEL = No observed adverse effect level; and LOAEL = Lowest observed adverse effect level. ( b). The dermal absorption factor = 6.4%. ( Note: The FIFRA Scientific Advisory Panel recommended use of a lower value of 2 3%. The occupational assessment in the risk assessment uses 6.4 percent dermal absorption because the handlers and workers are exposed to the arsenic residue from the aqueous solution during mixing, loading, and handling or are exposed to newly treated, or " wet' wood which has arsenic residues on the surface of the wood). ( c). For inhalation exposure, a default absorption factor of 100% is used. Route to route extrapolation is used to estimate the exposed dose. ( d). Inhalation unit risk ( IUR) is derived from a 24 hour exposure inhalation unit risk with a value of 4.3 x 10 3 ( µ g/ m3) 1. To convert the IUR to a cancer slope factor in units of ( mg/ kg/ day)  1 for the general population = IUR ( µ g/ m3) 1 x 1/ 70 kg x 20 m3/ day x 1 mg/ 1,000 µ g ( EPA, 1989). ( e). For workers working 8 hour per day, the inhalation cancer slope factor ( CSF) derived from the 24 hour IUR for general population, is adjusted for an 8 hour work day. CSF for 8 hr work day = general population CSF of 15.1 ( mg/ kg/ day) 1 x ( 8hrs/ 24 hrs) = 5.0 ( mg/ kg/ day) 1. ( f). CSF is derived from the risk assessment associated with inorganic in drinking water are presented in 2000. The 2001 National Research Council ( NRC) update made specific recommendation with respect to the overall cancer risk estimates. The Agency is currently considering these recommendations and their potential impact on the cancer potency estimate. Based on the Agency's considerations of these recommendations, the current proposed cancer potency number may change in the final version of this risk assessment. 17 Chromium VI Hexavalent chromium, or Cr( VI), is a strong skin irritant. In addition, Cr( VI) is a strong skin allergen. The potent skin allergenicity of chromium( VI) has been well documented in the literature, and chromium( VI) compounds have been reported to be the most frequent sensitizing agent in man. Most of the occurrences of contact dermatitis cited are the results of occupational exposures. For previously sensitized individuals, very low dosage of Cr( VI) can elicit allergic contact dermatitis. In addition, a variety of animal models including guinea pigs and mice have conclusively demonstrated that hexavalent chromium is a potent skin sensitizer. Therefore, the Committee concluded that the skin irritation and the skin allergenicity effects are the primary concern for Cr( VI) through the dermal exposure route. No end point will be selected for risk assessment. The risk concern of the dermal contact of Cr( VI) should be addressed through precautionary labeling statements.

Consistent with Agency practice, the endpoint for the inhalation risk assessment is taken from the 1998 IRIS update for chromium VI and applies to all durations of inhalation exposure. The epidemiological study of workers in the chrome plating industry by Linberg and Hedenstierna, 1983 was selected for the LOAEL. The authors concluded that 8 hour exposure to chromic acid above the LOAEL value of 0.002 mg/ m3 can be identified for incidence of nasal septum atrophy following exposure to chromic acid mists in chrome plating facilities. At TWA exposures greater than 0.002 mg/ m3, nasal septum ulcerations and perforations occurred in addition to the atrophy reported at lower concentrations. A LOAEL of 0.002 mg/ m3 is based on an 8 hour TWA occupational exposure. No one exposed to levels below 0.001 mg/ m3 complained of subjective symptoms.

The ambient air concentration of 0.002 mg/ m3 was then converted to a dose in units of mg/ kg/ day for comparison with inhalation doses estimated in this exposure assessment. Therefore, the air concentration in the epidemiological study was multiplied by an inhalation rate of 8 m3/ workday ( light activity of 16.7 L/ min or 1 m3/ hour) and divided by a body weight of 70 kg to arrive at a LOAEL of 2.3 x 10 4 mg/ kg/ day. The EPA recommended target MOE of 100 is used for this risk assessment for all durations ( i. e., 10x intra variability for human study, 3x for lack of a NOAEL, and 3x modifying factor for epidemiological study and to convert to a long term or " lifetime" duration).

The cancer endpoint for inhalation exposure is classified as group A ( known human carcinogen) with an 24 hour continuous inhalation unit risk ( IUR) of 1.2x10 2 (

g/ m3) 1 ( Table 2b). The 24 hour inhalation unit risk was adjusted for an 8 hour work day for assessing cancer risks to workers ( i. e., adjustment is 8 hr work day / 24 hr day). Human carcinogenicity by the oral route of exposure cannot be determined and chromium is classified as group D. 18 Table 2b. Toxicological Endpoints for Assessing Occupational Exposures/ Risks to Chromium ( VI)

EXPOSURE SCENARIO DOSE ( mg/ kg/ day) ENDPOINT STUDY Acute Dietary This risk assessment is not required.

Chronic Dietary This risk assessment is not required.

Incidental Shortand Intermediate Term Oral ( a) NOAEL= 0.5of chromic acid [ 0.12 of Cr( VI)]

MOE = 100 based on the increased incidence of maternal mortality and decreased body weight gain at LOAEL of 2.0 [ 0.48 of Cr ( VI)] Developmental/ Rabbit Tyl, 1991 Dermal Exposure ( b)

( All Durations) Because dermal irritation and dermal sensitization are the primary concern through the dermal exposure route, no toxicological end point is selected for use in assessing dermal exposure risks to chromium.

Inhalation Exposure ( All Durations) ( a) LOAEL= 0.002 mg/ m3; ( or 2.3 x 10 4 mg/ kg/ day) MOE = 100 nose and throat symptoms observed at the 0.002 mg/ m3 level Linberg and Hedenstierna, 1983.

Carcinogenicity  Inhalation ( Inhalation Risk) CSF= 40.6 ( c)( mg/ kg/ day) 1 ( For general Population) Lung tumors IRIS CSF= 13.5 ( d)( mg/ kg/ day) 1 ( For 8 hour working day)

Note: ( a). MOE = Margin of Exposure; NOAEL = No observed adverse effect level; and LOAEL = Lowest observed adverse effect level. ( b). The dermal absorption factor for Cr( VI) = 1.3% for handler dermal contact with chromated arsenical pesticides. ( c) The 24 hours inhalation unit risk is 1.16 x 10 2 ( µ g/ m3) 1 which can also be expressed as 0.0116 m3/

g. To convert the air concentration to a dose to yield units of kg day/ mg or ( mg/ kg/ day) 1 the unit risk is expressed mathematically as 0.0116 m3/

g x day/ 20 m3 x 1000

g/ mg x 70 kg = 40.6 ( mg/ kg/ day) 1 ( EPA, 1989). ( d) For workers working 8 hour per day, the inhalation cancer slope factor ( CSF) derived from the 24 hour CSF for the general population, is adjusted for an 8 hour work day . CSF for 8 hr work day = general population CSF of 40.6 ( mg/ kg/ day) 1 x ( 8hrs/ 24 hrs) = 13.5 ( mg/ kg/ day) 1.

( c) Dermal Absorption Arsenic: For arsenic ( V), the short, intermediate, and long term dermal and oral cancer endpoints are based on toxicity endpoints from oral studies. A dermal absorption rate of 6.4 percent was applied to oral exposure estimates to establish risks reflective of a dermal endpoint, as recommended in the HIARC report. ( It should be noted that in Agency discussions held with the FIFRA Scientific Advisory Panel on October 23 25, 2001, the panel recommended use of a lower value of 2 3 percent. However, the occupational assessment in the PRA uses 6.4 percent dermal absorption because the handlers and workers are exposed to the arsenic residue from the aqueous solution during mixing, loading, and handling or are exposed to newly treated, or " wet' wood which has arsenic residues on the surface of the wood )

Chromium VI: A dermal exposure risk assessment was not conducted for chromium due to the lack of toxicological endpoint selection. However, dermal absorption factors were established ( U. S. EPA, 2002). A 19 dermal absorption value for chromium ( VI) of 1.3 percent is to be used for handler dermal contact with chromated arsenical wood preservative pesticides. CCA treated wood contains mainly Cr ( III) after fixation has occurred.

B. Occupational Exposures ( 1) Handler Exposures EPA has determined that there are potential exposures to mixers, loaders, applicators, and other handlers during typical use patterns associated with CCA and related pesticides. The inorganic arsenicals ( CCA) are restricted use chemicals which can only be applied by certified applicators, primarily in commercial and industrial settings for pressure wood preservative treatments.

( a) Occupational Handlers One scenario was developed to best represent the pressure treatment use pattern. A brief description of the scenario that describes exposure to occupational handlers is presented in Table 3.

( 2) Handler Exposure Data and Assumptions ( a) Handler Exposure Data In the course of the occupational exposure chapter development for this RED, chemical specific handler data submitted by industry and identified from pertinent literature sources were reviewed for use in developing exposure estimates for worker populations. Certain studies are presented in this section as an overview of the available data, yet only data from the ACC Worker Exposure Study ( MRID 455021 01) ( ACC, 2001) were used in developing appropriate occupational scenarios for wood treatment plant workers involved with pressure treatments. 20 Table 3. Exposure Scenarios for Occupational Handlers Exposure Scenarios Scenario Descriptions Data Source Pressure Treatmentsa ( 1) Applying diluted chromated arsenical liquid treatment solutions at a pressure treatment plant using an automated/ closed delivery system. Scenario involves using an automated/ closed delivery system to mechanically pump a 1 2% CCA C treatment solution from the " work tank" to the pressure treatment cylinder ( i. e., retort) to pressure treat a charge of wood. Exposure may occur to treatment operators and treatment assistants while handling leads and charge chains, opening and closing retort doors, cleaning and maintenance of systems. Treatment operators operate and monitored application system valves and controls, they sometimes opened and closed cylinder doors, and they supervised the insertion and removal of charges ( loads of dried, debarked poles or untreated ties) of poles from the treatment cylinders American Chemistry Council ( ACC, 2001).

a Representative handler scenarios related to applications of CCA C chromated arsenical products at wood pressure treatment plants. b Representative handler scenarios related to remedial applications of chromated or chromated arsenical products to pressure treated wooden poles, posts, lumber, or other timbers.

Legend: CCA  C = Chromated Copper Arsenate, Type C with the following composition on a 100% oxide basis: 47.5% Hexavalent Chromium, as CrO3; 18.5% Copper, as CuO; 34.0% Arsenic, as As2O5.

( b) Chemical Specific Handler Exposure Data ACC's Worker Exposure Study ( MRID 455021 01)

The handler exposure assessments for pressure treatment scenarios were completed by EPA using the data from the study titled " Assessment of Potential Inhalation and Dermal Exposure Associated with Pressure Treatment of Wood with Arsenical Products" ( MRID 455021 01). In this study three commercial facilities in the U. S. and Canada were examined to determine the dermal and inhalation exposure of workers applying CCA and ACZA end use products to dimensional lumber, outdoor furniture components, utility poles and/ or posts by pressure treatment systems. The three facilities and the end use products used in this study were said to represent a range of geographic locations, formulations used, species of wood products treated, and application parameters used for treatment of wood with CCA.. 21 The CCA study measured both handlers and post application activities. Although there is overlap in job functions, the handlers are defined as the treating operators ( TO) and treating assistants ( TA). Three sites were monitored in the CCA study: ( 1) Site A South Carolina, ( 2) Site B Ontario, and ( 3) Site C Oregon. The TO were monitored at Sites A, B, C using 5 replicates at each site. The TA were monitored at Sites A and C using 5 replicates at each site. The post application activities included: tram setter ( TS) at Site A ( n= 5); stacker operator ( SO) at Site A ( n= 4); loader operator ( LO) at Sites A, B, C ( n= 15); supervisor ( S) at Site B ( n= 5); test borer ( TB) at Site C ( n= 5); and the tallyman ( TM) at Site C ( n= 5).

The U. S. and Canadian sites indicate a difference in the mean dermal exposures. Upon further analysis by Health Canada it was determined that the final vacuum for the pressure treatment process was not performed at site B. The final vacuum is used to remove excess CCA. The final vacuum process was performed for 1 to 5 hours at site A and 2 to 3 hours at site C. According to the AWPA standard, the final vacuum procedure is a recommended practice and this practice appears to reduce the potential for dermal and inhalation exposures as indicated in Table 3a. These data will be considered during the risk mitigation phase of the RED process. 22 Table 3a. Pressure Treatment CCA Unit Exposures Normalized to the Treatment Solution Concentration for Comparison Among Sites.

Site Treatment Solution Statistic Dermal UE (

g As/ ppm) Inhalation UE (

g As/ m3/ ppm) % ppm All sites ( A, B, C)  Handler Treatment Operator ( n = 15) 0.438 to 0.595 4380 to 5950 Average ± std 2.04 ± 2.68 0.00032 ± 0.00038 Median 0.37 0.00013 90th percentile 5.39 0.00092 Maximum 7.74 0.0011 US sites ( A and C)

Handler Treatment Operator ( n = 10) 0.544 and 0.595 5440 and 5950 Average ± std 0.27 ± 0.16 0.00008 ± 0.00004 Median 0.23 0.00005 90th percentile 0.45 0.00013 Maximum 0.60 0.00013 Canadian site ( B)  Handler Treatment Operator ( n = 5) 0.438 4380 Average ± std 5.6 ± 1.2 0.00077 ± 0.00026 Median 5.2 0.00084 90th percentile 6.9 0.0010 Maximum 7.7 0.0011 US sites ( A and C)

Handler Treatment Assistant ( n = 10) 0.544 and 0.595 5440 and 5950 Average ± std 0.24 ± 0.14 0.0001 ± 0.00004 Median 0.23 0.00013 90th percentile 0.40 0.00013 Maximum 0.52 0.00014 Canadian site ( B)  Handler Treatment Assistant ( n = 0) The treatment assistant ( TA) was not monitored at site B All sites ( A, B, C)

Postapplication All job functions ( TS, SO, LO, S, TB, TM)

( n = 39) 0.438 to 0.595 4380 to 5950 Average ± std 0.74 ± 0.73 0.00020 ± 0.00025 Median 0.42 0.00013 90th percentile 1.81 0.00050 Maximum 3.11 0.0011 US sites ( A and C)

Postapplication All job functions ( TS, SO, LO, TB, TM)

( n = 29) 0.544 and 0.595 5440 and 5950 Average ± std 0.49 ± 0.51 0.00013 ± 0.00015 Median 0.35 0.00005 90th percentile 1.2 0.00039 Maximum 2.0 0.00055 Canadian sites ( B)

Postapplication All job functions ( LO and S)

( n = 10) 0.438 4380 Average ± std 1.5 ± 0.80 0.00039 ± 0.00039 Median 1.4 0.00017 90th percentile 2.2 0.00096 Maximum 3.1 0.0010 ppm = (% treatment solution) * ( 10,000) Air concentration was calculated as

g collected per sample per ppm / ( 480 min per day x 2 L/ min) 23 At each site, pressure treatment of wood products was performed using the same basic process. Workers operated self propelled or stationary loaders which moved untreated poles or dimensional lumber from holding areas and stacked them onto wheeled metal trams on a railroad track leading into the treatment cylinder( s). When enough trams were loaded to fill a cylinder, the poles or ties on each tram were tied together with chains of metal or plastic bands. A charge cable ( or " lead cable") was connected to the tram load of wood products farthest from the cylinder door, and was laid along the top of the stacked items on the trams. The filled trams made up a " charge" of wood products.

The cylinder door was opened either hydraulically or manually and its drawbridge was positioned so that it connected the drip pad track with the cylinder's interior rails. The charge was then pushed into the cylinder by a self propelled loader or a self pulled into the cylinder by an automated transfer deck. Workers placed the free end of the lead cable into the cylinder, closed the cylinder door( s), and started the treatment process. Treating solution was then pumped from storage tanks into the cylinder, after which pressure ( 120  180 psi) was applied to the cylinder to allow the preservative to permeate the wood of the poles. CCA solutions were used unheated, while ACZA solutions were heated to 120 140  F during treatment.

After treatment, excess treating solution was removed from the cylinders and wood products by maintaining a vacuum in the cylinder for approximately 1 to 5 hours. The duration of a treatment cycle ranged from approximately 2 to 340 hours, depending on the species of wood treated, the procedures used by each site, and whether CCA or ACZA was being used. At the end of treatment, the cylinder was opened, and a mist containing water and some preservative was observed.

Workers removed the charge from the cylinder by removing the end of the lead cable from the cylinder and attached it to a hook on a self propelled loader, which then pulled the loaded trams out of the cylinder. At Sites A, B, and C, each charge was pulled onto a concrete " drip pad," where excess treatment solution was allowed to drip from the wood products and trams onto the pad for up to several hours. After site personnel removed lead cables and chains, the poles were pushed by the loader to a storage area, where workers using hand or electric powered drills took narrow cores of wood from selected poles or ties to determine the depth of penetration of the preservative, and the amount of preservative that was actually absorbed by the wood. Charges that did not contain enough CCA or did not penetrate deep enough were retreated as above.

Sixteen workers were monitored for this study for 4 5 consecutive work days each. On each day of monitoring, one or more loads of dried, debarked poles or posts, or cut dimensional lumber or other wood products were stacked on moveable trams, and pushed into horizontal cylinders. Each cylinder was filled with a mixture containing arsenic pentoxide, copper oxide, and either chromium oxide or zinc oxide wood. The treated wood absorbed between approximately 41 lbs and 1,011 lbs of total metal oxides per charge, depending on the charge volume and treatment parameters.

The treatment plant job categories monitored in this study include treatment operators, treating assistants, loader operators, test borers, tram setter, tally man, and stacker operator. Workers performed typical tasks related to these activities and were monitored for up to 4 5 consecutive work days each. 24 Descriptions of the tasks monitored are bulleted below :

 Treatment operators ( TOs)  TOs operate and monitored application system valves and controls, they sometimes opened and closed cylinder doors, and they supervised the insertion and removal of charges ( loads of dried, debarked poles or untreated ties) of poles from the treatment cylinders.

 Treating assistant ( TA)  TAs performed many of the same functions as the TOs and sometimes assisted the TO in charge preparation, cylinder cleaning and maintenance, filter cleaning, mixing of treatment solution, and also participated in some loader operations moving charges.

 Loader operators ( CLOs in the cylinder area, and LLOs in the load out areas)  LOs stacked untreated wood onto charge trams, moved charges into and out of treatment cylinders, distribute treated wood to load out area, and loaded treated wood for shipment.

 Test borers ( TBs)  TBs cut cores from freshly treated poles or ties for testing for CCA.

 Tram setter ( TS) At Site A TS steam cleaned drip pads and tracks, Operated cylinder door controls, cleaned cylinders, handled hazardous waste, and manually moved trams and placed drawbridges for treatments.

Dermal exposure levels were estimated by passive dosimetry using whole body dosimeters ( WBD) worn under the worker's clothing and lightweight cotton glove dosimeters worn under work gloves. The dermal exposure levels to CCA and ACZA were estimated by measuring the levels of arsenic, chromium, copper, and zinc compounds. Each analyte was determined in all WBD and glove samples. Dermal exposure to arsenic and Cr are depicted in Tables 4 and 5.

Table 4. Geometric Mean Daily Dermal Exposure Levels for Monitored Workers at all Sites for Arsenic Parameter Dermal Exposure (

g/ kg bw/ day) to Arsenic a TO TA TB TS TM LO S SO No. Replicates 15 10 5 5 5 15 5 4 Minimum 4.02 6.24 1.59 69.1 26.8 10.0 20.4 13.8 Maximum 472 39.2 8.29 148 151 190 86.8 29.0 Mean 128 19.1 3.51 102 56.8 56.9 57.0 21.3 S. D. 161 11.1 2.74 30.7 53.2 53.6 31.9 6.23 G. M. 47.9 16.3 2.91 98.0 44.3 38.0 48.3 20.6 Median 30.4 18.2 2.46 89.8 32.2 35.0 66.5 21.1 * Abbreviations: LO = Loader operator; S= supervisor, SO= stacker operator, TA = treating assistant, TB= test borer, TM= tally man, TO= treating operator, and TS= tram setter. 25 Table 5. Geometric Mean Daily Dermal Exposures for Monitored Workers at all Sites for Chromium ( VI)

Parameter Dermal Exposure (

g/ kg bw/ day) to Hexavalent Chromium a TO TA TS LO S SO No. Replicates 10 5 5 10 5 4 Minimum 2.02 1.43 1.75 1.48 1.78 1.41 Maximum 10.3 12.9 11.8 4.01 3.84 1.58 Mean 4.83 4.00 5.74 2.45 2.60 1.49 S. D. 3.04 5.00 3.82 0.91 0.893 0.068 G. M. 4.07 2.61 4.74 2.31 2.49 1.49 Median 3.40 1.80 5.83 2.1 2.15 1.48 a Abbreviations: LO = Loader operator, TA = treating assistant, TB= test borer, TM= tally man, and TO= treating operator.

Inhalation exposures for each worker were estimated by active dosimetry. Each worker wore a sampling train consisting of a 37mm polyvinyl chloride ( PVC) filter in a plastic cassette, attached to the front of the work shirt with the intake orifice in the breathing zone. The intake orifice was oriented downward and connected by Tygon ® tubing to a second cassette, attached to a Buck S. S. Pump on the work belt. The pump drew air through the sampling filter at approximately 2 L/ min while the subject performed the tasks. Pumps were calibrated immediately prior to and after each monitoring period using a NIST traceable calibrated Sierra ® Top Trak   mass flow meter. The results of the sampling are presented in Tables 6, 7, and 8.

Table 6. 8 Hour Inhalation Air Concentrations ( µ g/ m3)

Test Site Job Class Total As Total Cu Total Cr Hex Cr Total Zn A TA 0.803 1.001 1.41 0.268

TS 2.09 2.37 2.87 0.330

TO 0.648 0.980 1.45 0.269

LO 0.527 1.011 1.36 0.340

SO 0.267 1.08 0.508 0.267

B LO 2.25 4.58 3.31 0.309

S 1.26 2.82 2.84 0.342

TO 3.85 5.24 3.88 0.298

C TB 0.279 0.347   0.279 TO 0.287 0.862   0.358 LO 0.270 0.810   0.419 TM 0.362 0.561   0.362 26 TA 0.347 0.835   0.538 Table 7. Geometric Mean Daily Inhalation Exposure Levels for Monitored Workers at all Sites for Arsenic Parameter Inhalation Exposure (

g/ kg bw/ day) to Arsenic a TO TA TB TS TM LO S SO No. Replicates 15 10 5 5 5 15 5 4 Minimum 0.031 0.032 0.033 0.101 0.033 0.032 0.113 0.032 Maximum 0.709 0.102 0.035 0.434 0.104 0.676 0.319 0.033 Mean 0.205 0.073 0.034 0.282 0.049 0.157 0.167 0.033 S. D. 0.233 0.033 0.001 0.119 0.031 0.213 0.086 0.000 G. M. 0.107 0.065 0.034 0.256 0.044 0.086 0.154 0.033 Median 0.098 0.095 0.034 0.298 0.038 0.092 0.138 0.033 a Abbreviations: LO = Loader operator; S= supervisor, SO= stacker operator, TA = treating assistant, TB= test borer, TM= tally man, TO= treating operator, and TS= tram setter.

Table 8. Geometric Mean Daily Inhalation Exposure Levels for Monitored Workers at all Sites for Hexavalent Chromium Parameter Inhalation Exposure (

g/ kg bw/ day) to Hexavalent Chromium a TO TA TS LO S SO No. Replicates 10 5 5 10 5 4 Minimum 0.033 0.032 0.031 0.031 0.038 0.032 Maximum 0.037 0.034 0.101 0.098 0.049 0.033 Mean 0.0 35 0.033 0.046 0.042 0.042 0.033 S. D. 0.002 0.001 0.031 0.020 0.005 0.000 G. M. 0.035 0.033 0.040 0.040 0.042 0.033 Median 0.035 0.033 0.033 0.038 0.040 0.033 a Abbreviations: LO = Loader operator; S= supervisor, SO= stacker operator, TA = treating assistant, TB= test borer, TO= treating operator, and TS= tram setter.

PEL Monitoring Data A study by the former Chemical Manufacturer's Association ( CMA) entitled the " Report on Monitoring of Workers in Wood Treating Plants Using Arsenical Pressure Treatment Wood Preservatives under RPAR PEL Requirements" was submitted to EPA for review and as part of the ongoing registration requirements for industrial air monitoring reporting. The CMA inhalation exposure study summarized monitoring data for airborne arsenic in wood treating plants that used CCA and AZCA. The monitoring data were collected from 220 wood treating plants in the United States between 1991 and 1999 under the Rebuttable Presumption Against the Registration ( RPAR) PEL monitoring program. In 27 addition, two studies originally conducted for the National Institute for Occupational Safety and Health ( NIOSH) were also submitted by the registrant to EPA ( MRID 426337 11 and 426337 13).

In 1984, EPA issued a position document requiring certain changes in the terms and conditions for registration of wood preservative uses of inorganic arsenicals as part of the RPAR ( U. S. EPA, 1984). Under this notice, wood treating plants are required to either provide employees with respirators or to implement a PEL monitoring program. Under the PEL monitoring program, if the airborne concentration of arsenic is above 10 µ g/ m3, employees are required to wear respirators. If the airborne concentration is between 5 µ g/ m3 and 10 µ g/ m3, air monitoring is required every six months until at least two consecutive measurements taken at least seven days apart, are below 5 µ g/ m3. Once levels are below 5 µ g/ m3 when this criteria is met, the wood treating plant can discontinue monitoring. The wood treating plants are also required to submit the air monitoring data to EPA on an annual basis. The wood treating plants are required to submit the air monitoring data to the registrants. The results of the PEL monitoring study are displayed in Table 9.

Table 9. Statistical Summary of Inhalation Exposure Levels of Airborne Arsenic in Wood Treating Plants Using Chromated Copper Arsenate ( CCA), As Collected under the PEL Program Job Categories Number of Replicates Inhalation Exposure Levels of Airborne Arsenic ( µ g/ m3)

Mean Standard Deviation Geometric Mean Maximum Minimum Treating Operator 458 2.89 6.33 0.44 55 0.007 Forklift Operator 215 2.56 5.22 0.52 47.7 0.01 Drip Pad Worker 127 2.76 5.32 0.41 37.8 0.002 Lumber Stacker 17 0.67 1.31 0.25 5.3 0.03 Lumber Tagger 14 1.27 1.74 0.19 4.7 0.01 Maintenance 6 3.53 3.85 0.86 10.51 0.03 The PEL monitoring data for airborne arsenic in pressure treatment plants only partially met the requirements specified in the Occupational and Residential Test Guideline 875.1400 Indoor Inhalation Exposure. Note that there are few deficiencies in this study with respect to data quality ( see Data Gaps, Uncertainties and Limitations Section 7). 28 NIOSH Studies ( MRID 426337 11 and 426337 13)

Two CCA inhalation exposure studies were conducted by NIOSH and were submitted by the registrant to EPA ( MRID 426337 11 and 426337 13). These studies examined the specific exposure using a 50 percent and 60 percent CCA Type C ( CCA C) product. These studies examined the inhalation exposure of both arsenic and chromium, but are not compliant to the Series 875 Occupational and Residential Test Guidelines. A few of these deficiencies are described in the Uncertainties and Limitations Section of this report.

The study entitled " Review of Industrial Hygiene Report, Comprehensive Survey of Wood Preservative Treatment Facility at Cascade Pole Company McFarland Cascade, Tacoma Washington" ( MRID 426337 13) was conducted to quantify the exposure to chromated copper arsenate ( CCA) [ as well as other wood preservative chemicals: pentachlorophenol ( PCP), creosote and ammoniacal copper arsenate ( ACA)] and to evaluate potential health risks under typical operating conditions. This site was selected as best representing a large diversified wood treating facility which uses CCA. The survey also included a medical industrial hygiene and safety program at the facility. The study was completed in 1980 as an Industrial Hygiene report and is not FIFRA compliant. Only the information relevant to CCA will be included in this review.

The employees with the most potential exposure are the six treatment plant operators ( two per shift), six pettibone and two fork lift operators, in addition to two to four yard crew. Wood treated with CCA is kiln dried or steam processed prior to pressure treatment. The CCA lumber is treated with CCAC CCA Type C 50 percent concentrate is diluted with water to a 1 2 percent treatment solution, which is used to pressure treat the wood. The concentrate is pumped from a tanker truck where it is diluted in a 10,000 gallon work tank. The wood treated in this manner is usually dimensional lumber. It is dried, incised and treated for 4 5 hours under pressure at ambient temperatures.

The industrial hygiene survey included personal air sampling, area air sampling and wipe/ touch samples on semi dry CCA treated wood before and after flushing with water. Integrated breathing zone and area sampling was conducted using Bendix BDX 41 air sampling pumps. The pumps were pre and post calibrated using a Universal Pump calibrator ( Model 302) and the appropriate collection devices. The CCA treatment process was evaluated using the NIOSH P& CAM # 173 air sampling method for Copper and Chromium and S 309 for arsenic. The sampling train consisted of a 8 micron millipore AA filter with a cellulose back up pad in a 37 mm 3 piece closed faces cassette at a collection rate of 1.8 2.0 liters per minute. The samples were analyzed by Atomic Absorption ( AA) Spectroscopy.

Treatment helper and treatment operator exposures were monitored for one 18 minute cylinder opening exposure period. In addition, exposure was monitored for a treatment operator during a series of 4 cylinder openings, which lasted a total of 72 minutes and exposure for treatment helper during a series of three cylinder openings lasting 80 minutes. The results are summarized in Table 10. 29 Table 10: Personal Air Sampling Information for CCA ( MRID 426337 13)

Operation Chromium (

g/ m3) Arsenic (

g/ m3)

Treatment Helper  cylinder opening & discharging ( 18 min.) < 27.8 < 8.3 Treatment Operator  cylinder opening & discharging ( 18 min.) < 31.2 < 9.4 Treatment Operator  cylinder opening & discharging ( 72 min.) Series of 4 cylinder openings 6.8 3265.3 Treatment Helper  cylinder opening & discharging ( 80 min.) Series of 3 cylinder openings 6.3 4.5 1980 Occupational exposure limits: Chromic Acid 100

g/ m3, Arsenic 500

g/ m3.

An additional NIOSH study entitled " Industrial Hygiene Surveys of Occupational Exposures to Wood Preservative Chemicals" ( MRID 426337 11) also quantified the occupational exposure to workers during pressure treatment using chromated copper arsenate ( CCA) as well as pentachlorophenol ( PCP), creosote and ammoniacal copper arsenate ( ACA). Although the survey was conducted at eleven wood treatment plants and two manufacturing operations in 1981 as part of an industry wide evaluation of worker exposure to wood preservative chemicals, personal air sampling and wipe/ touch samples were conducted at only one site. For this site, the treatment process was similar to the previous NIOSH study, and sampling methodologies used were not adequately explained. The results are summarized in Tables 11 and 12.

Table 11: Personal Air Sampling Information for CCA ( MRID 426337 11)

Operation Chromium (

g/ m3) Arsenic (

g/ m3)

Treatment Helper  cylinder opening & discharging ( 18 min.) < 31 < 9 Treatment Operator  cylinder opening & discharging ( 18 min.) < 28 < 8 Treatment Operator  cylinder opening & discharging ( 72 min.) < 7 3265 Treatment Helper  cylinder opening & discharging ( 80 min.) 6 4 1980 Occupational exposure limits: Chromic Acid 100

g/ m3, Arsenic 500

g/ m3.

Table 12: Personal Air Sampling Information for CCA ( MRID 426337 11)

Operation Hexavalent Chromium (

g/ m3) Chromium (

g/ m3) Arsenic (

g/ m3)

Treatment building adjacent concentrate mix tank 0.3 < 1.9 0.9 Adjacent cylinder door opening < 0.2 < 3.1 < 0.6 Top of freshly treated wood < 0.3 < 3.3 < 0.7 30 Table 13: Exposure Assumptions for Amount of Chromated Arsenical Wood Preservatives Handled Per Day Exposure Scenarios for Non Pressure Treatments Pounds ai used ( 1) Applying diluted chromated arsenical liquid treatment solutions at a pressure treatment plant using an automated/ closed delivery system. Not Applicable to calculate for this scenario. Based on ACC Worker Exposure Study Data ( MRID 455021 01)

( 3) Handler Risk Assessment and Characterization ( a) Handler Exposure and Non Cancer Risk Calculations Exposure to occupational handler exposures are presented in Table 14. For Scenario ( 1), dermal and inhalation exposures were developed using geometric mean values from chemical specific worker exposure study data for treatment operators and treatment assistants at pressure treatment plants ( ACC, 2001). The occupational handler daily dose and lifetime average daily dose ( LADD) are presented in Table 14. The associated occupational handler noncancer MOE's and cancer risks based on the registrant's pressure treatment study are presented in Table 15. 31 Table 14. Occupational Short, Intermediate, and Long term Handler Doses to CCA Dermal Inhalation Exposure Scenario ( Scen. #) Dermal Unit Exposure ( mg/ lb ai) a Inhalation Unit Exposure ( µ g/ lb ai) b Chemical of Concern % CCA in End Use Product Amount Ingredient Handled per Dayc Short, Intermediate and Long Term Daily Dosed Lifetime Average Daily Dosee Short, Intermediate, and Long term Daily Dosef Lifetime Average Daily Dosee ( 1) Treatment Operator ( TO) and Treatment Assistant ( TA)

Applying Liquid Formulations at Pressure Treatment Plants using an Automatic/ Closed Delivery System ( Opening and Closing the Retort) ACC Study Data Used ( See Table 4) ACC Study Data Used ( See Tables 7 & 8) Arsenic ( As) 2% N/ A 3.07E 3 ( TO) 1.12E 3 ( TO) 1.07E 4 ( TO) 3.9E 5 ( TO)

Chromium g ( Cr+ 6) N/ A NA NA 3.5E 5 ( TO) 1.3E 5 ( TO)

Arsenic ( As) 2% N/ A 1.04E 3 ( TA) 3.8E 4 ( TA) 6.5E 5 ( TA) 2.4E 5 ( TA)

Chromiumg ( Cr+ 6) N/ A NA NA 3.3E 5 ( TA) 1.2E 5 ( TA)

Footnotes:

a For Scenario ( 1) ACC Worker Exposure Study Data, geometric mean value for As in Table 4 used for Treatment Operator ( TO) and Treatment Assistant ( TA) ( MRID 455021 01).

b For Scenario ( 1) ACC Worker Exposure Study Data, geometric mean values for As and Cr+ 6 in Tables 7 & 8, used for TO and TA ( MRID 455021 01).

c Amounts handled per day are based on the CCA worker exposure study for pressure treatments.

d Short, intermediate, and long term daily dermal dose ( mg/ kg/ day) = geo mean daily dermal dose for As in Table 4 in units of

g/ kg x 0.001 mg/

g unit conversion x ( ABS/ 100). ABS is 6.4% for arsenic.

e Lifetime average daily dose, LADD ( mg/ kg/ day) = geo mean daily dermal or inhalation dose from Tables 4, 7, 8 in units of

g/ kg x 0.001 mg/

g unit conversion x dermal ABS/ 100 x ( 250 days worked per yr/ 365 days per year) x ( 40 working years/ 75 yr lifetime).

f Short, Intermediate, and long term daily inhalation dose ( mg/ kg/ day) = geo mean daily inhalation dose for As or Cr+ 6 from Tables 7 and 8 in units of

g/ kg x 0.001 mg/

g unit conversion.

g Represents the hexavalent portion of chromium.

NA Not applicable 32 Table 15. Occupational Short, Intermediate, and Long term Handler Risks to CCA Exposure Scenario ( Scen. #) Chemical of Concern Risk Mitigation Amount Ingredient Handled per Daya Dermal Inhalation Short, and Intermediateterm MOEb Long term MOEc Cancer Riskd Short, and Intermediateterm MOEe Long term MOE f Cancer Riskg ( 1) Applying Liquid Formulations at Pressure Treatment Plants using an Automatic/ Closed Delivery System ( Opening and Closing the Retort)

( treatment operator TO) Arsenic ( As) Engineering Controls N/ A 16 0.3 4.1E 3 467 7 2.0E 4 Chromium ( Cr + 6) N/ A N/ A N/ A NA 7 ( Target MOE 30) 7 ( Target MOE 100) 1.7E 4 ( treatment assistant TA) Arsenic ( As) Engineering Controls N/ A 48 0.8 1.4E 3 769 12 1.2E 4 Chromium ( Cr+ 6) N/ A N/ A N/ A NA 7 ( Target MOE 30) 7 ( Target MOE 100) 1.6E 4 Footnotes:

a Amount handled per day based on the CCA worker exposure study for pressure treatments.

b MOE = dermal LOAEL / short term, intermediate term dermal daily dose. Where As LOAEL = 0.05 mg/ kg/ day.

c MOE = dermal NOAEL / long term dermal daily dose. Where As NOAEL = 0.0008 mg/ kg/ day.

d Dermal Cancer Risk = cancer slope factor ( CSF) x dermal LADD. Where arsenic CSF = 3.67 ( mg/ kg/ day) 1 .

e MOE = inhalation LOAEL / short term, intermediate term inhalation daily dose. Where As LOAEL = 0.05 mg/ kg/ day and Cr+ 6 LOAEL = 2.3 x 10 4 mg/ kg/ day ( derived from a LOAEL = 0.002 mg/ m3).

f MOE = inhalation NOAEL or LOAEL / long term inhalation dose. Where As NOAEL = 0.0008 mg/ kg/ day and Cr+ 6 LOAEL = 2.3 x 10 4 mg/ kg/ day ( derived from a LOAEL = 0.002 mg/ m3).

g Inhalation Cancer Risk = Cancer slope factor ( CSF) x inhalation LADD. Where arsenic CSF for an 8 hour work day = 5 ( mg/ kg/ day) 1 and Cr+ 6 inhalation CSF = 13.5 ( mg/ kg/ day) 1.

NA Not applicable NOTE: Recommended Dermal MOE for Arsenic: short and intermediate term = 30 ( 10x intraspecies variation and 3x for the use of the LOAEL); long term = 3 ( 3x rather than 10x because of the large sample size in the toxicity study (> 40,000)).

Recommended Inhalation MOE for Arsenic: short and intermediate term = 100 ( 10x intraspecies variation and 3x for the use of the LOAEL), long term = 3 ( 3x rather than 10x because of the large sample size in the toxicity study (> 40,000)).

Recommended Inhalation MOE for Chromium VI: all durations = 100 ( 10x intraspecies variation, 3x for use of a LOAEL, and 3x modifying factor for epidemiological study and to convert to a long term or " lifetime" duration). 33 Daily Inh. Exposure mg ai day

Air Concentration

g m3 x CF mg

g x IR m3 hr x ED hr day Daily Inhalation Dose mg ai kg/ day

Daily Inhalation Exposure. mg day 1 Body Weight ( kg) ( i) Inhalation Exposure Chemical specific inhalation data from the ACC Worker Exposure Study were available for Scenario ( 1). The daily inhalation exposure from air concentration was calculated as follows:

Air Concentration = Values obtained from ACC study CF ( 0.001 mg/ µ g) = conversion factor ED ( hr/ day) = exposure duration IR ( m3/ hr) = inhalation rate Where:

IR ( inhalation rate) = 1.25 m3/ hr ( EPA, 1997)

ED ( exposure duration) = 8 hrs/ day ( ii) Inhalation Dose Short, intermediate, and long term inhalation doses were calculated where data were available for arsenic and chromium VI. Inhalation doses were calculated using a body weight of 70 kilograms,

because the endpoint is not sex specific. Daily inhalation dose is calculated as follows:

Daily Inhalation Exposure ( mg ai/ day) = calculated from CCA exposure study ( ½ LOD)

Body Weight ( kg) = 70 For Scenario ( 1), the ACC Study Data, calculated geometric mean values in Tables 7 & 8 were used directly after a CF ( 0.001 mg/ µ g) was applied. 34 Inhalation MOE

LOAEL ( mg/ kg/ day) Inhalation Dose ( mg/ kg/ day)

Daily Dermal Dose mg ai Kg/ Day

Daily Dermal Exposure mg ai day x 1 Body Weight ( Kg) x ABS (%) ( iii) Inhalation Risk Inhalation risks from short, intermediate, and long term exposures to arsenic and chromium VI were calculated where applicable. The following formula describes the calculation of an inhalation MOE:

For the arsenic assessment a LOAEL of 0.05 mg/ kg/ day was used for the short term and intermediate term exposures ( uncertainty factor of 100), and a NOAEL of 0.0008 mg/ kg/ day was used for long term arsenic inhalation estimates ( uncertainty factor of 3 applied).

For the chromium VI assessment a LOAEL of 0.002 mg/ m3 was used for all durations. The ambient air concentration of the LOAEL was then converted to a dose in units of mg/ kg/ day for comparison with inhalation doses estimated in this exposure assessment. Therefore, the air concentration of the LOAEL was multiplied by the inhalation rate of 8 m3/ workday and divided by a body weight of 70 kg to arrive at a LOAEL of 2.3 x 10 4 mg/ kg/ day. The EPA recommended target MOE of 100 is used for this risk assessment for all durations ( i. e., 10x intra variability for human study, 3x for lack of a NOAEL, and 3x modifying factor for epidemiological study and to convert to a long term or " lifetime"

duration).

( iv) Dermal Exposure For Scenario ( 1), the ACC Study Data, calculated geometric mean values in Tables 4 & 5 were used directly after a CF ( 0.001 mg/ µ g) and dermal absorption values were applied.

( v) Dermal Dose A body weight of 70 kilograms was used to calculate the daily dermal dose for short,

intermediate and long term exposures to arsenic.

Body Weight ( kg) = 70 for short, intermediate and long term exposures to arsenic and short,

intermediate, and long term exposures to chromium ABS = 6.4 percent absorption for arsenic 35 Dermal MOE

NOAEL ( mg/ kg/ day) Dermal Dose ( mg/ kg/ day)

LADD mg ai kg/ day

[ Chronic Dermal Dose ( mg/ kg/ day) or Chronic Inhalation Dose ( mg/ kg/ day)] x EF ( days/ yr) x ED ( yrs) 365 days/ yr x Lifetime ( yrs)

Risk

LADD mg ai kg/ day x Cancer Slope Factor 1 ( mg/ kg/ day) ( vi) Dermal Risk To calculate risks to handlers, the daily dermal doses of arsenic and chromium received by handlers were compared to the dermal endpoints of concern. The following formula describes the calculation of a dermal MOE:

The following endpoints were used to assess dermal risks from exposures to arsenic:

NOAEL = 0.05 mg/ kg/ day for short and intermediate term dermal exposures with an uncertainty factor of 30; and

NOAEL = 0.0008 mg/ kg/ day for long term dermal exposures with an uncertainty factor of 3.

( b) Handler Exposure and Cancer Risk Calculations For assessing the cancer risks, the lifetime average daily dermal dose was calculated using the chronic ( long term) dose ( dermal or inhalation, whichever is applicable), and accounting for exposure frequency ( EF), exposure duration ( ED), and average length of lifetime. Exposure duration was assumed to be 40 years and is the standard value used by OPP to represent a working lifetime. This is assumed to be a conservative value. Lifetime is assumed to be 75 years, the recommended value for the U. S.

population, as cited in EPA's Exposure Factors Handbook ( U. S. EPA, 1997). Exposure frequency is scenario specific. Table 16 details the exposure frequency values and handler cancer risk estimates. All handler scenarios assume an exposure frequency of 250 days per year ( i. e., 5 days per week, 50 days per year). This is a standard Agency assumption for days worked per year. The following formula describes the calculation of the lifetime average daily dose ( LADD):

When a cancer slope factor is the cancer endpoint selected, cancer risk is calculated by multiplying the lifetime average daily dose times the cancer slope factor using the following formula: 36 Arsenic Cancer Risk: For assessing the cancer risks from exposures to arsenic based on the oral ingestion cancer endpoint, the LADD was calculated using the chronic ( long term) dermal dose.

Exposure frequency, exposure duration, and average length of lifetime were also accounted for in the calculation. A cancer slope factor of 3.67 ( mg/ kg/ day) 1 was the endpoint selected for the oral ingestion cancer endpoint.

The inhalation cancer slope factor of 15.1 ( mg/ kg/ day) 1 is for the general population and was derived from a continuous 24 hour exposure inhalation unit risk value of 4.3 x 10 3 ( µ g/ m3) 1 or 0.0043 m3/  g. To convert the air concentration to a dose to yield units of kg day/ mg or ( mg/ kg/ day) 1 the unit risk is expressed mathematically as 0.0043 m3/  g x day/ 20 m3 x 1000  g/ mg x 70 kg = 15.1 ( mg/ kg/ day)

1. To adjust for an 8 hour work day, the general population, continuous 24 hour exposure CSF of 15.1 ( mg/ kg/ day) 1 is multiplied by 8 hr/ 24 hr yielding a CSF of 5 ( mg/ kg/ day) 1 for worker exposure.

Chromium VI Cancer Risk: For assessing the cancer risks from exposures to chromium VI based on the inhalation cancer endpoint, the lifetime average daily inhalation dose was calculated using the chronic ( long term) inhalation dose. Exposure frequency, exposure duration, and average length of lifetime were also accounted for in the calculation. The general population, continuous 24 hour cancer slope factor of 40.6 ( mg/ kg/ day) 1 was derived from an inhalation unit risk of 1.2 x 10 2 (  g/ m3) 1. To adjust for an 8 hour work day, the general population, continuous 24 hour exposure CSF of 40.6 ( mg/ kg/ day) 1 is multiplied by 8 hr/ 24 hr yielding a CSF of 13.5 ( mg/ kg/ day) 1 for worker exposure.

( c) Occupational Handler Scenarios with Non Cancer Dermal Risk Concerns Some of the MOE's for the dermal exposure scenarios presented in the risk assessment exceed the Agency's level of concern for short, intermediate and long term dermal exposures to arsenic. Dermal exposures that exceed the Agency's level of concern for short and intermediate ( i. e., MOEs < 30) and long term ( i. e., MOEs < 3) for arsenic and chromium are presented below. 37 Arsenic Short Term and Intermediate Term ° Applying Liquid Formulations at Pressure Treatment Plants Using an Automatic/ Closed Delivery System ( Opening and Closing the Retort) [ treatment operator ( TO)] ( MOE of concern, MOE = 16);

Long Term ° Applying Liquid Formulations at Pressure Treatment Plants Using an Automatic/ Closed Delivery System ( Opening and Closing the Retort) [ treatment operator ( TO) and treatment assistant ( TA)] ( MOEs of concern, MOEs = 0.3 for TO, and 0.8 for TA);

Chromium VI: Since dermal irritation and dermal sensitization are the primary exposure concerns through the dermal route, no toxicological endpoint was selected for use in assessing dermal exposure risks to chromium. Risk mitigation will continue to be addressed through appropriate precautionary labeling statements.

( d) Occupational Handler Scenarios with Non Cancer Inhalation Risk Concerns Arsenic: The MOEs for the inhalation exposure scenarios presented in the risk assessment do not exceed the Agency's level of concern ( i. e., MOEs < 100) for short term and intermediate term exposures to arsenic.

Chromium VI: Although all of the inhalation exposure samples were below the limit of detection, the MOEs for the inhalation exposure using ½ LOD still exceed the Agency's level of concern ( i. e. MOEs < 100) for short term, intermediate term, and long term durations. Inhalation MOEs for chromium are presented below.

Short Term, Intermediate Term, and Long Term ° Applying Liquid Formulations at Pressure Treatment Plants Using an Automatic/ Closed Delivery System ( Opening and Closing the Retort) [ treatment operator ( TO) and treatment assistant ( TA)] ( MOEs of concern, MOEs = 7 for TO, and 7 for TA);

( e) Occupational Handler Scenarios with Cancer Risk Concerns Dermal and Inhalation Exposure: Cancer Carcinogenic endpoints related to lifetime dermal and inhalation exposures to arsenic, and inhalation exposure to chromium VI have been identified. In general, the Agency is concerned when occupational cancer risk estimates exceed 1 x 10 4 ( E 4) . The Agency will seek ways to mitigate the 38 risks, to the extent that it is practical and economically feasible, to lower the risks to 1 x 10 6 ( E 6) or less. The following handler scenarios have cancer risks between 1 x 10 5 ( E 5) and 1 x 10 2 ( E 2) at the assessed level of mitigation. Cancer risks for each scenario are presented in Table 16.

Arsenic:

Lifetime Dermal Cancer Risk ( > E 4 )

° Applying Liquid Formulations at Pressure Treatment Plants Using an Automatic/ Closed Delivery System ( Opening and Closing the Retort) [ treatment operator ( TO) and treatment assistant ( TA)] ( risks of concern = 4.1E 3 for TO, and 1.4E 3 for TA ); and Lifetime Inhalation Cancer Risk ( > E 4 )

° Applying Liquid Formulations at Pressure Treatment Plants Using an Automatic/ Closed Delivery System ( Opening and Closing the Retort) [ treatment operator ( TO) and treatment assistant ( TA)] ( risks of concern = 2.0E 4 for TO, and 1.2E 4 for TA); and Chromium VI:

Lifetime Inhalation Cancer Risk ( > E 4 )

° Applying Liquid Formulations at Pressure Treatment Plants Using an Automatic/ Closed Delivery System ( Opening and Closing the Retort) [ treatment operator ( TO) and treatment assistant ( TA)] ( risks of concern = 1.7E 4 for TO, and 1.6E 4 for TA); and ( 4) Postapplication Exposures and Risks The Agency has determined that there are potential exposure concerns relating to postapplication exposure to CCA. There are potential exposures following applications of concentrated chromated arsenical preservatives in industrial settings and chromated arsenical end use products manufactured for commercial, industrial, and residential use sites. The potential individual postapplication exposures are outlined below in the occupational postapplication sections.

( a) Occupational Postapplication Exposure Postapplication exposure occurs following the application of a pesticide product. In the wood pressure treatment plants, postapplication occurs when job functions require that there be contact with freshly treated wood and pressure treatment machinery ( e. g. retort door) or pipes. Or when occupying treatment areas directly after pesticide applications. A brief description of the worker job functions/ activities for treatment plant workers used in developing the occupational postapplication scenarios is presented in Table 16. Postapplication exposures attributed to workers involved with nonpressure treatment use patterns were not assessed in this document. . 39 Table 16. Exposure Scenarios for Occupational Postapplication Exposures Exposure Scenario Scenario Description Pressure Treatment Activities ( 1) Loader Operator Scenario pertains to a formulating facility or wood pressure treatment facility. Worker operates self propelled vehicles that are used to load wood products onto and off of trams, and to move charges into and out of treatment cylinders and to and from load out areas. Worker may perform certain out of cab tasks such as collect tank samples, perform test boring and lab analysis of treatment solutions of wood.

( 2) Test Borer Scenario pertains to a wood pressure treatment facility. Worker takes pole cores to test for CCA penetration. May also test concentration of lots of CCA, and perform other QC laboratory duties.

( 3) Tram Setter Positions trams for loading, places wood spacers on trams where needed to elevate wood to be treated. Does all lead and chain handling for that site. Removes and shreds all bands from treated stacks of lumber. Sweeps and pressure washes pad areas. Picks up and disposes of treated wood waste. May also perform various labor and cleanup duties in drip pad area.

( 4) Supervisor Supervisor duties were not fully described in the study report.

( 5) Tally Man Main duties include counting and inspection of incoming and outgoing truckloads of wood products, and supervision of loading and unloading of lumber trucks at drip pad and elsewhere. May also perform some treatment related duties, such as end marking of treated items or chaining of charges for treatment. His office was located immediately adjacent to the drip pad.

( 6) Stacker Operator Operates a lumber stacking device, which arranges treated boards in stacks for banding and shipment to customers, and removes wood spacer sticks from bundles of treated boards. This worker manually positions ends of all treated boards moving through device so they are evenly positioned.

( 5) Occupational Postapplication Data, Assumptions, Exposure, and Risk Calculations ( a) Postapplication Data " Assessment of Potential Inhalation and Dermal Exposure Associated with Pressure Treatment of Wood with Arsenical Products" ( MRID 455021 01) submitted by the American Chemistry Council ( ACC, 2001). This study was described in more detail in section B. 2. a ( Handler Exposure Data section). Postapplication exposure was assessed using the results of the ACC study based on the exposure analyses for the Loader Operator, Test Borer, Tram Setter, Stacker Operator, and Tally Man. Note that these job functions represent the bulk of the monitored worker tasks which included postapplication activities. The data for these studies were presented in Tables 4, 5, 7 and 8 in Section B. 2. a and were used to establish exposure doses and risks for this assessment. In addition to the ACC study which was used to develop the human exposure chapter, two CCA specific inhalation studies were also submitted to EPA for review ( MRID 447595 02 and the PEL RPAR study).

A study by the Chemical Manufacturer's Association ( CMA) entitled the " Report on Monitoring of Workers in Wood Treating Plants Using Arsenical Pressure Treatment Wood Preservatives under RPAR PEL Requirements" was submitted to EPA as part of the reregistration requirements. This study 40 summarized monitoring data for airborne arsenic in wood treating plants using CCA and AZCA. The monitoring data were collected between 1991 and 1999 from 220 wood treating plants in the United States, under the RPAR PEL monitoring program. Table 17 provides the airborne arsenic levels of the PEL study. Chromium exposure data were not presented in the PEL RPAR study.

Another worker inhalation study ( MRID 447595 02) that assessed exposures to CCA, creosote, and pentachlorophenol was completed in 1982 by Koppers Company, Inc. and was submitted to EPA via the CMA Biocides Panel, Arsenic Acid Task Force on February 4, 1999. This study assessed the exposures of pressure treatment plant employees involved in the production of treated wood products in five pressure treatment facilities. Limited information was provided regarding the sampling methods and the quality assurance ( QA) and quality control ( QC) of the study. Although this study did not provide QA/ QC information and is not current, it presents chromium exposure information. Study results are presented in Table 18. Because the the CMA studies did not fully meet Series 875 guidelines, the ACC study was used exclusively to evaluate occupational postapplication exposure.

Table 17. Statistical Summary of Inhalation Exposure Levels of Airborne Arsenic in Wood Treating Plants Using CCA Collected under the PEL Program Job Categories Number of Replicates Inhalation Exposure Levels of Airborne Arsenic ( µ g/ m3)

Mean Standard Deviation Geometric Mean Maximum Minimum Forklift Operator 215 2.56 5.22 0.52 47.7 0.01 Drip Pad Worker 127 2.76 5.32 0.41 37.8 0.002 Lumber Stacker 17 0.67 1.31 0.25 5.3 0.03 Lumber Tagger 14 1.27 1.74 0.19 4.7 0.01 Maintenance 6 3.53 3.85 0.86 10.51 0.03 41 Inhalation MOE

Inhalation LOAEL ( mg/ kg/ day) Inhalation Dose ( mg/ kg/ day) Table 18. Inhalation Exposure to CCA in a Pressure Treatment Process using 8 hour Time Weighted Averages ( TWAs)

Job Classification # of Workers Monitored Chromium ( Cra) Arsenic ( As)

Lift Truck Operator 29 GM < 5.6 ± 3.0 Range < 0.9 27 GM 1.4 ± 3.5 Range 0.03 15 Stacker 24 GM < 2.1 ± 2.2 Range < 1.2 7 GM 1.0 ± 2.5 Range 0.05 7 Striker 5 GM < 4 ± 2.0 Range < 1.2 7 GM 2.2 ± 6.5 Range 0.03 3 Maintenance 3 GM 8.7 ± 1.4 Range 6 12 GM 2.2 ± 3.9 Range 0.6 9 Plant Office 3 GM 0.3 ± 3.2 Range 0.1 1 GM 0.1 ± 1.5 Range 0.1< 0.2 All Exposures 70 GM 3.2 ± 3.1 Range 0.1 27 GM 1.1 ± 3.1 Range 0.03 15 a GM geometric mean and geometric standard deviation Range minimum and maximum concentrations ( b) Short, Intermediate, and Long Term Inhalation Exposure and Non Cancer Risk Calculations The postapplication inhalation exposure assessments were completed by EPA using the chemicalspecific data from MRID 455021 01 which examined postapplication exposures to workers in CCA pressure treatment facilities. For these scenarios, the doses were already presented in the study report ( see Tables 7 and 8). Geometric mean doses were used in the MRTD 455021 01 study and are presented in Table 19. Occupational postapplication non cancer MOE's and cancer risks are presented in Table 20.

( i) Inhalation Dose Inhalation doses were already presented in the ACC study ( MRID 455021 01). The results of this study were used directly in this report.

( ii) Inhalation Risk Inhalation risks from short, intermediate, and long term exposures to arsenic and chromium have been identified. The following formula describes the calculation of an inhalation MOE: 42 For the arsenic assessment a LOAEL of 0.05 mg/ kg/ day was used for the short term and intermediate term exposures ( uncertainty factor of 100), and a NOAEL of 0.0008 mg/ kg/ day was used for long term arsenic inhalation estimates ( uncertainty factor of 3 applied).

For the chromium VI assessment a LOAEL of 0.002 mg/ m3 was used for all durations. The ambient air concentration of the LOAEL was then converted to a dose in units of mg/ kg/ day for comparison with inhalation doses estimated in this exposure assessment. Therefore, the air concentration of the LOAEL was multiplied by the inhalation rate of 8 m3/ workday and divided by a body weight of 70 kg to arrive at a LOAEL of 2.3 x 10 4 mg/ kg/ day. The EPA recommended target MOE of 100 is used for this risk assessment ( i. e., 10x intra variability for human study, 3x for lack of a NOAEL, and 3x modifying factor for epidemiological study and to convert to a long term or " lifetime" duration). 43 Table 19. Occupational Short, Intermediate, and Long term Postapplication Doses to CCA Dermal a Inhalation b Exposure Scenario ( Scen. #) Chemical of Concern Short, Intermediate,

and Long Term Daily Dose ( mg/ kg/ day) c Lifetime Average Daily Dose ( mg/ kg/ day) e Short, Intermediate,

and Long term Daily Dose ( mg/ kg/ day) d Lifetime Average Daily Dose ( mg/ kg/ day) e ( 1) Loader Operator ( LO) Arsenic ( As) 0.0024 0.00089 8.6E 5 3.1E 5 Chromium ( Cr+ 6) NA NA 4.0E 5 1.5E 5 ( 2) Test Borer ( TB) Arsenic ( As) 0.00019 6.8E 5 3.4E 5 1.2E 5 Chromium ( Cr+ 6) NA NA NA NA ( 3) Tram Setter ( TS) Arsenic ( As) 0.0063 0.0023 2.56E 4 9.4E 5 Chromium ( Cr+ 6) NA NA 4.0E 5 1.5E 5 ( 4) Supervisor ( S) Arsenic ( As) 0.0031 0.0011 1.54E 4 5.6E 5 Chromium ( Cr+ 6) NA NA 4.2E 5 1.5E 5 ( 5) Tally Man ( TM) Arsenic ( As) 0.0028 0.0010 4.4E 5 1.6E 5 Chromium ( Cr+ 6) NA NA NA NA ( 6) Stacker Operator ( SO) Arsenic ( As) 0.0013 0.00048 3.3E 5 1.2E 5 Chromium ( Cr+ 6) NA NA 3.3E 5 1.2E 5 Footnotes:

a Dermal exposure is based on MRID 455021 01. See Table 4 for geometric mean dermal exposure for As.

b Inhalation exposure is based on MRID 455021 01. See Tables 7 & 8 for geometric mean inhalation exposures for As and Cr+ 6.

c Calculations for short, intermediate, and long term dermal daily dose ( mg/ kg/ day) = geo mean daily dermal dose for As in Table 4 in units of

g/ kg x 0.001 mg/

g unit conversion x ( ABS/ 100). ABS is 6.4% for arsenic.

d Calculations for short, intermediate, and long term inhalation daily dose ( mg/ kg/ day) = geo mean daily inhalation dose for As or Cr+ 6 from Tables 7 and 8 in units of

g/ kg x 0.001 mg/

g unit conversion..

e Lifetime Average Daily Dose, LADD ( mg/ kg/ day) = geo mean daily dermal or inhalation dose from Tables 4, 7, 8 in units of

g/ kg x 0.001 mg/

g unit conversion x dermal ABS/ 100 x ( 250 days worked per yr/ 365 days per year) x ( 40 working years/ 75 yr lifetime).

NA Not applicable 44 Table 20. Occupational Short, Intermediate, and Long term Postapplication Risks to CCA Exposure Scenario ( Scen. #) Chemical of Concern Dermal Inhalation Short,

and Intermediateterm MOEa Long term MOEb Cancer Riskc Short,

and Intermediateterm MOEd Long term MOEe Cancer Riskf ( 1) Loader Operator ( LO) Arsenic ( As) 21 0.3 3.3E 3 581 9 1.6E 4 Chromium ( Cr+ 6) NA NA NA 6 6 2.0E 4 ( 2) Test Borer ( TB) Arsenic ( As) 27 4 2.5E 4 1471 24 6.3E 5 Chromium ( Cr+ 6) NA NA NA NA NA NA ( 3) Tram Setter ( TS) Arsenic ( As) 8 0.1 8.4E 3 195 3 4.7E 4 Chromium ( Cr+ 6) NA NA NA 6 6 2.0E 4 ( 4) Supervisor ( S) Arsenic ( As) 16 0.3 4.1E 3 325 5 2.8E 4 Chromium ( Cr+ 6) NA NA NA 6 6 2.1E 4 ( 5) Tally Man ( TM) Arsenic ( As) 18 0.3 3.8E 3 1136 18 8.0E 5 Chromium ( Cr+ 6) NA NA NA NA NA NA ( 6) Stacker Operator ( SO) Arsenic ( As) 38 0.6 1.8E 3 1515 24 6.0E 5 Chromium ( Cr+ 6) NA NA NA 6 6 1.6E 4 Footnotes:

a Short and Intermediate term dermal MOE = dermal NOAEL / Short and Intermediate term dermal daily dose ( mg/ kg/ day). Where As LOAEL = 0.05 mg/ kg/ day.

b Long term MOE = dermal NOAEL/ Long term dermal daily dose ( mg/ kg/ day). Where As NOAEL = 0.0008 mg/ kg/ day.

c Dermal Cancer Risk = slope factor x dermal LADD. Where arsenic cancer slope factor = 3.67 ( mg/ kg/ day) 1 .

d Short, Intermediate term inhalation MOE = inhalation NOAEL / Short, Intermediate term inhalation dose ( mg/ kg/ day). Where As LOAEL = 0.05 mg/ kg/ day, and Cr + 6 LOAEL = 2.3 x 10 4 mg/ kg/ day ( derived from a LOAEL = 0.002 mg/ m3).

e Long term inhalation MOE = inhalation NOAEL or LOAEL / long term inhalation dose. Where As NOAEL = 0.0008 mg/ kg/ day and Cr+ 6 LOAEL = 2.3 x 10 4 mg/ kg/ day ( derived from a LOAEL = 0.002 mg/ m3).

f Inhalation Cancer Risk = cancer slope factor x inhalation LADD. Where arsenic cancer slope factor for an 8 hour work day = 5 ( mg/ kg/ day) 1 and Cr+ 6 inhalation cancer slope factor = 13.5 ( mg/ kg/ day) 1.

NA Not applicable NOTE: Recommended Dermal MOE for Arsenic: short and intermediate term = 30 ( 10x intraspecies variation and 3x for the use of the LOAEL); long term = 3 ( 3x rather than 10x because of the large sample size in the toxicity study (> 40,000)).

Recommended Inhalation MOE for Arsenic: short and intermediate term = 100 ( 10x intraspecies variation and 3x for the use of the LOAEL), long term = 3 ( 3x rather than 10x because of the large sample size in the toxicity study (> 40,000)).

Recommended Inhalation MOE for Chromium VI: All durations = 100 ( 10x intraspecies variation, 3x for use of a LOAEL, and 3x modifying factor for epidemiological study and to convert to a long term or " lifetime" duration). 45 Dermal MOE

Dermal NOAEL ( mg/ kg/ day) Dermal Dose ( mg/ kg/ day)

Lifetime Average Daily Dose mg ai kg/ day

[ Chronic Dose ( mg/ kg/ day)] x EF ( days/ yr) x ED ( yrs) 365 days/ yr x Lifetime ( yrs) ( c) Short, Intermediate, and Long Term Dermal Exposure and Non Cancer Risk Calculations The postapplication dermal exposure assessments were completed by EPA using the chemicalspecific data from ACC's MRID 455021 01 which examined postapplication exposures to workers in CCA pressure treatment facilities. For these scenarios, the doses were already presented in the study report ( see Tables 4 and 5). Geometric mean doses were used in the study and are presented in Table 19. Note that the dermal doses were adjusted by the appropriate dermal absorption factor to calculate an absorbed dose. This is done because the toxicity value is based on oral absorbed doses. Occupational postapplication non cancer MOE's and cancer risks are presented in Table 20.

( i) Dermal Dose Dermal doses were already presented in the ACC study ( MRID 455021 01). The doses used in this study were used directly in this report with the exception that the dermal doses were adjusted by the dermal absorption factor because the dermal toxicity information used is based on oral toxicity data.

( ii) Dermal Risk Dermal risks from short, intermediate, and long term exposures to arsenic and chromium have been identified. The following formula describes the calculation of an inhalation MOE:

The short and intermediate term LOAEL for arsenic is 0.05 mg/ kg/ day and the long term LOAEL for arsenic is 0.0008 mg/ kg/ day . The uncertainty factor used is 30 for short and intermediate term endpoints and 3 for long term endpoints. Because the dermal irritation and dermal sensitization of chromium are the primary concern through the dermal exposure route, no toxic endpoint is selected. The risk concern should be addressed through labeling.

( d) Postapplication Exposure Cancer Risk Calculations The following formula describes the calculation of the lifetime average daily dose: 46 Risk

LADD mg ai kg/ day x Cancer Slope Factor 1 ( mg/ kg/ day) Risk was calculated by multiplying the lifetime average daily dose times the cancer slope factor using the following formula:

( 6) Occupational Postapplication Risk Assessment and Characterization ( a) Postapplication Non Cancer Risks from Dermal Exposure Arsenic: Acute, subchronic, and chronic toxicity endpoints related to dermal exposures to arsenic have been identified. The Agency's level of concern for arsenic from dermal exposure is as follows: short term and intermediate term ( MOEs < 30) and long term ( MOEs < 3). All the scenarios that exceed the Agency's level of concern for dermal non cancer exposure for arsenic are presented below.

Short Term and Intermediate Term ° Loader Operator ( MOE of concern, MOE = 21); ° Tram Setter ( MOE of concern, MOE = 8); ° Supervisor ( MOE of concern, MOE = 16); ° Tally Man ( MOE of concern, MOE = 18); and ° Test Borer ( MOE of concern, MOE = 27).

Long Term ° Loader Operator ( MOE of concern, MOE = 0.3); ° Test Borer ( MOE of concern, MOE = 4); ° Tram Setter MOE of concern, ( MOE = 0.1); ° Supervisor ( MOE of concern, MOE = 0.3); ° Tally Man ( MOE of concern, MOE = 0.3); and, ° Stacker Operator ( MOE of concern, MOE = 0.6).

Chromium VI: Since dermal irritation and dermal sensitization are the primary exposure concerns through the dermal route, no toxicological endpoint was selected for use in assessing dermal postapplication exposure risks to chromium. Risk mitigation will continue to be addressed through appropriate precautionary labeling statements.

( b) Postapplication Non Cancer Risks from Inhalation Exposure Arsenic: Acute, sub chronic, and chronic toxicity endpoints related to inhalation exposures to arsenic have been identified. The Agency's level of concern for arsenic from inhalation exposure is as follows: short term and intermediate term ( MOEs < 100) and long term ( MOEs < 3). The MOEs for the inhalation exposure scenarios presented in the risk assessment do not exceed the Agency's level of concern. 47 Chromium VI: The MOEs for the inhalation exposure scenarios presented in the risk assessment exceed the Agency's level of concern for short term, intermediate term, and long term inhalation exposures to chromium VI ( i. e., MOEs < 100) based on the toxicological information for Chromium ( VI). Inhalation exposures at ½ LOD ( all samples non detect) are exceeded for all assessed postapplication exposure scenarios as follows:

Short Term, Intermediate Term, and Long Term ° Loader Operator ( MOE of concern, MOE = 6); ° Test Borer ( scenario not assessed for chromium); ° Tram Setter ( MOE of concern, MOE = 6); ° Supervisor ( MOE of concern, MOE = 6); ° Tally Man ( scenario not assessed for chromium); and, ° Stacker Operator ( MOE of concern, MOE = 6).

( c) Postapplication Dermal and Inhalation Scenarios with Cancer Risks Dermal and Inhalation Exposure: Cancer Carcinogenic endpoints related to lifetime dermal and inhalation exposures to arsenic, and inhalation exposure to chromium VI have been identified. In general, the Agency is concerned when occupational cancer risk estimates exceed 1 x 10 4 ( E 4) . The Agency will seek ways to mitigate the risks, to the extent that it is practical and economically feasible, to lower the risks to 1 x 10 6 ( E 6) or less. The following worker scenarios have cancer risks between 1 x 10 5 ( E 5) and 1 x 10 2 ( E 2) at the assessed level of mitigation. Occupational postapplication cancer risks for each scenario are presented in Table 20.

Arsenic:

Lifetime Dermal Cancer Risk ( > E 4 )

° Loader Operator ( risk of concern = 3.3E 3); ° Test Borer ( risk of concern = 2.5E 4); ° Tram Setter ( risk of concern = 8.4E 3); ° Supervisor ( risk of concern = 4.1E 3); ° Tally Man ( risk of concern = 3.8E 3); and, ° Stacker Operator ( risk of concern = 1.8E 3).

Lifetime Inhalation Cancer Risk ( > E 4 )

° Loader Operator ( risk of concern = 1.6E 4); ° Test Borer ( risk of concern = 6.3E 5); ° Tram Setter ( risk of concern = 4.7E 4); ° Supervisor ( risk of concern = 2.8E 4); ° Tally Man ( risk of concern = 8.0E 5); and, ° Stacker Operator ( risk of concern = 6.0E 5). 48 Chromium VI:

Lifetime Inhalation Cancer Risk ( > E 4 )

° Loader Operator ( risk of concern = 2.0E 4); ° Test Borer ( scenario not assessed for chromium); ° Tram Setter ( risk of concern = 2.0E 4); ° Supervisor ( risk of concern = 2.1E 4). ° Tally Man ( scenario not assessed for chromium); and, ° Stacker Operator ( risk of concern = 1.6E 4).

( 7) Data Gaps, Uncertainties, and Limitations ACC's Worker Exposure Study ( MRID 455021 01)

The study met most of Series 875 guideline requirements. The method validation, field fortifications, and QA/ QC were thoroughly explained; however, some minor issues are as follows: ( 1) differences in chemical usage versus exposure along with work practices among facilities were not examined thoroughly by EPA at this time; ( 2) data were corrected based on field recovery; however, only the corrected data were presented in the study; ( 3) the limit of detection for chromium VI was not sensitive enough based on the endpoints selected for the risk assessment; and ( 4) separate field fortifications were not collected for each worker. The CCA worker exposure study is currently under going additional analysis to determine the differences among the sites and to determine potential mitigation measures. Preliminary results indicate higher exposures at the Canadian site that are attributed to the lack of the final vacuum procedure during the pressure treatment process.

PEL Study A study by the Chemical Manufacturer's Association ( CMA) study entitled the " Report on Monitoring of Workers in Wood Treating Plants Using Arsenical Pressure Treatment Wood Preservatives under RPAR PEL Requirements" was submitted to EPA as part of the PEL monitoring program. Although these data were not used to calculate handler or postapplication inhalation exposures to arsenic or chromium, the major issues of concern with the PEL inhalation monitoring data are identified as follows:

° Guideline 875.1400 requires that five replicates each at a minimum of three representative indoor sites ( i. e., a total of 15 replicates) should be evaluated for each job category. In this study, for CCA, the number of replicates for job categories of lumber tagger and maintenance workers is less than 15.

° It could not be determined from the study report if QA/ QC samples required by Guideline 875.1400 were analyzed under the PEL monitoring program. These QA/ QC samples include field blanks, laboratory fortified samples, and field fortified samples.

° It could not be determined from the study report if the trapping efficiency for arsenic on the trapping medium was tested. 49 ° PEL data presents data only for inhalation exposure of arsenic and not inhalation exposure of chromium VI.

NIOSH studies Two CCA inhalation exposure studies were conducted by the National Institute for Occupational Safety and Health ( NIOSH) and were submitted by industry to EPA ( MRID 426337 11 and 426337 13). These data were not used to calculate handler exposures to arsenic or chromium for this RED chapter. No postapplication exposures were examined in this study. The major issues of concern with the NIOSH inhalation monitoring data are identified as follows:

° The study was conducted in 1980 as a Industrial Hygiene Report and was not meant to be a FIFRA compliant study under 875 Subdivision U requirements.

° The study was conducted at only one facility where a maximum of three air sampling replicates were collected. FIFRA requirements stipulate at least five replicates at each of at least three test sites for each job function.

° Information was not provided on the amount of each active ingredient handled by the test subjects.

° Insufficient data were provided on the sample storage stability and extraction efficiency.

° Quality control procedures for this study were unacceptable. The study did not include any field blanks. Both reagent and method blanks should have been prepared.

° There were no field or laboratory spikes for the air sampling trains to check the recoveries of the method, nor any quantification limits provided.

° This study should have also included dosimeter sampling on the workers to determined actual dermal exposure while working.

° Exposure to arsenic for the treatment operator and treatment helper during retort opening varied by three orders of magnitude.

° A FIFRA compliant study would need to be conducted in order to adequately evaluate the risk at these type of facilities.

Another study ( MRID 447595 02) of worker inhalation exposure to CCA, Creosote, and Pentachlorophenol was completed in 1982 by Koppers Company, Inc. and was submitted to EPA via the CMA Biocides Panel, Arsenic Acid Task Force on February 4, 1999. This study assessed the postapplication exposures of pressure treatment plant employees involved in the production of treated wood products in five pressure treatment facilities. Limited information was provided regarding the sampling methods and the quality assurance ( QA) and quality control ( QC) of the study. This study does not provide QA/ QC information and is not current and has not been used in this risk assessment. 50 ( 8) Results Summary Handler The results of the handler exposure and risk assessment indicate that short, intermediate, and longterm risks for dermal and inhalation exposures exceed the level of concern for arsenic for some of the handler scenarios. For arsenic, a margin of exposure ( MOE) of 30 or more for short and intermediateterm dermal risk is considered acceptable and an MOE of 3 or more is considered acceptable for longterm risks. Handler risks for dermal exposure of arsenic are exceeded for some scenarios.

The MOEs for the inhalation exposure scenarios presented in the risk assessment do not exceed the Agency's level of concern for short, and intermediate iterm inhalation exposures to arsenic ( i. e., MOEs < 100) based on the toxicological information for arsenic. However, an assessed scenario exceeded the Agency's level of concern for long term inhalation exposures to arsenic ( i. e., MOE < 3).

The MOEs for the inhalation exposure scenarios presented in the risk assessment exceed the Agency's level of concern for short, intermediate and long term inhalation exposures to chromium VI ( i. e. MOEs < 100) for some of the handler scenarios based on the toxicological information for Chromium ( VI).

In addition, cancer risks for all handler dermal and inhalation scenarios exceed the level of concern ( 1E 04) for occupational handlers. A summary table is presented later in this section that provides each exposure pathway in the RED; the overall results of the MOE and cancer risk evaluations; and identification of any additional data that would prove useful in reducing the uncertainties of the MOE and cancer risks.

Postapplication Many of the MOEs for the dermal exposure scenarios presented in the risk assessment exceed the Agency's level of concern for short, intermediate and long term dermal exposures to arsenic.

The MOEs for the inhalation exposure scenarios presented in the risk assessment do not exceed the Agency's level of concern for short, and intermediate inhalation exposures to arsenic ( i. e., MOEs< 100) based on the toxicological information for arsenic.

The MOEs for the inhalation exposure scenarios presented in the risk assessment exceed the Agency's level of concern for short, intermediate and long term inhalation exposures to chromium VI ( i. e. MOEs < 30) for some of the postapplication scenarios based on the toxicological information for Chromium ( VI).

In addition, cancer risks for all handler dermal and inhalation scenarios exceed the level of concern ( 1E 04) for postapplication. A summary table of each exposure pathway in the RED; the overall results of the MOE and cancer risk evaluations; and identification of any additional data that would prove useful in reducing the uncertainties of the MOE and cancer risks is presented as follows: 51 ( i) Summary Table Table 21 summarizes all the exposure scenarios and the sources of data used in developing this RED chapter.

Table 21. Summary of the Occupational Exposure Scenarios Data Exposure Scenario Source of Data Occupational Handler Pressure Treatments ( 1) Applying diluted chromated arsenical liquid treatment solutions at a pressure treatment plant using an automated/ closed delivery system ( opening and closing the retort). ACC Worker Exposure Study Data ( e. g. data for treatment operator and treatment assistant) ( ACC, 2001)

Occupational Postapplication Pressure Treatments ( 1) Loader Operator ACC Worker Exposure Study Data ( ACC, 2001) ( 2) Test Borer ( 3) Tram Setter ( 4) Supervisor ( 5) Tally Man ( 6) Stacker Operator Non Pressure Treatments ( 1) Pole Installers No data. Scenario not assessed.

( ii) Noncancer MOEs and Cancer Risks Occupational Handler ° Scenario 1 exceeds all arsenic dermal MOEs for treatment operator and long term MOEs for treatment assistant, and exceeds all chromium inhalation MOEs and all cancer risk criteria.

Occupational Postapplication 52 ° Scenario 6 exceeds ( iii) Data Gaps and Limitations The following is a summary of basic data gaps and limitations.

° Chromium inhalation exposure data were not available for postapplication exposure for scenarios 3 and 5. 53 3.0 REFERENCES American Chemistry Council ( ACC), 2001. Arsenical Wood Preservatives Task Force. Assessment of Potential Inhalation and Dermal Exposure Associated with Pressure Treatment of Wood with Arsenical Products. MRID 455021 01. September 24, 2001.

Chemical Manufacturer's Association ( CMA), 1999a. Memorandum from Hasmukh Shah, Manager, Arsenical Wood Preservative Task Force to Nathan Mottl, Environmental Scientist, Versar, Inc. Subject: Application Information on Osmoplastic ® Wood Preserving Compound, EPA Reg. No. 3008 68. April 27, 1999.

Chemical Manufacturer's Association ( CMA), 1999b. Memorandum from Hasmukh Shah, Manager, Arsenical Wood Preservative Task Force to Doreen Aviado, Biologist, U. S. Environmental Protection Agency, Antimicrobial Division. Subject: Application Information on Osmose Special K 33 Preservative, EPA Reg. No. 3008 21. May 5, 1999.

Chemical Manufacturer's Association ( CMA), 1999c. Memorandum from Hasmukh Shah, Manager, Arsenical Wood Preservative Task Force to Nathan Mottl, Environmental Scientist, Versar, Inc. Subject: Application Information on Hollow Heart ® Concentrate, EPA Reg. No. 3008 8. April 6, 1999.

PHED Surrogate Exposure Guide. 1998. Estimates of Worker Exposure from the Pesticide Handler Exposure Database. Version 1.1. August 1998.

U. S. EPA, 1984. " Wood Preservative Pesticides: Creosote, Pentachlorophenol, Inorganic Arsenicals. Position Document 4." Registration Division. Office of Pesticides and Toxic Substances. Washington, D. C. July, 1984.

U. S. EPA, 1989. Risk Assessment Guidance for Superfund. Volume I. Human Health Evaluation Manual ( Part A). Interim Final. Office of Emergency and Remedial Response. Washington, D. C. EPA/ 540/ 1 89/ 002.

U. S. EPA, 1997. Exposure Factors Handbook. Volume I III. Office of Research and Development. Washington, D. C. EPA/ 600/ P 05/ 002Fa.

U. S. EPA, 1998. Series 875 Occupational and Residential Exposure Test Guidelines, Group BPostapplication Exposure Monitoring Test Guidelines, Version 5.4. Office of Pesticide Programs, Health Effects Division. February 1998.

U. S. EPA, 2002. Inorganic Arsenic  Report of the Hazard Identification Assessment Review Committee; Inorganic Chromium  Report of the Hazard Identification Assessment Review Committee. J. Chen, S. Malish, and T. McMahon. April 15, 2002.