DRAFT Didecyl Dimethyl Ammonium Chloride ( DDAC)

Preliminary Risk Assessment ( DP Barcode 069149)

Office of Pesticide Programs Antimicrobials Division U. S. Environmental Protection Agency 1801 South Bell St. Arlington, VA 22202 Date: April 18, 2006 Page 2 of 52 TABLE OF CONTENTS 1.0 EXECUTIVE SUMMARY ......................................................................................................................... 3 2.0 PHYSICAL AND CHEMICAL PROPERTIES ...................................................................................... 7 3.0 ENVIRONMENTAL FATE........................................................................................................................ 8 4.0 HAZARD CHARACTERIZATION.......................................................................................................... 9 4.1 HAZARD PROFILE ........................................................................................................................................ 9 4.2 FQPA CONSIDERATIONS........................................................................................................................... 12 4.3 DOSE RESPONSE ASSESSMENT ................................................................................................................. 12 4.4 ENDOCRINE DISRUPTION .......................................................................................................................... 13 5.0 EXPOSURE ASSESSMENT AND CHARACTERIZATION.............................................................. 14 5.1 SUMMARY OF REGISTERED USES.............................................................................................................. 14 5.2 DIETARY EXPOSURE AND RISK ................................................................................................................. 14 5.3 DRINKING WATER EXPOSURES AND RISKS............................................................................................... 16 5.4 RESIDENTIAL EXPOSURE/ RISK PATHWAY ................................................................................................ 16 6.0 AGGREGATE RISK ASSESSMENT AND RISK CHARACTERIZATION................................... 20 6.1 ACUTE AND CHRONIC AGGREGATE RISKS ............................................................................................... 20 6.2 SHORT AND INTERMEDIATE TERM AGGREGATE EXPOSURES AND RISKS.............................................. 21 7.0 CUMULATIVE EXPOSURE AND RISK.............................................................................................. 23 8.0 OCCUPATIONAL EXPOSURE ASSESSMENT .................................................................................. 24 8.1 OCCUPATIONAL HANDLER EXPOSURES.................................................................................................... 24 8.2 OCCUPATIONAL POST APPLICATION EXPOSURES..................................................................................... 26 8.3 WOOD PRESERVATION.............................................................................................................................. 27 8.3.1 Non Pressure Treatment Scenarios ( Handler and Post application)............................................... 27 8.3.2 Pressure Treatment Scenarios ( Handler and Post Application)....................................................... 30 8.4 DATA LIMITATIONS/ UNCERTAINTIES ....................................................................................................... 31 9.0 INCIDENT REPORTS ............................................................................................................................... 32 10.0 ENVIRONMENTAL RISKS..................................................................................................................... 33 11.0 REFERENCES ............................................................................................................................................ 36 APPENDIX A: MASTER DDAC LABEL.............................................................................................................. 41 Page 3 of 52 1.0 EXECUTIVE SUMMARY This document provides a risk assessment for the Group I Quat Cluster. The Group I Quat Cluster is a group of structurally similar quaternary ammonium compounds (" quats") that are characterized by having a positively charged nitrogen covalently bonded to two alkyl group substituents ( at least one C8 or longer) and two methyl substituents. In finished form, these quats are salts with the positively charged nitrogen ( cation) balanced by a negatively charged molecule ( anion). The anion for the quats in this cluster is chloride or bromide. In this document, the Group I Quat Cluster will be referred to as DDAC ( didecyl dimethyl ammonium chloride).

DDAC is the active ingredient in numerous types of products. The products are mainly disinfectants and deodorants that are used in agricultural, food handling, commercial/ institutional/ industrial, residential and public access, and medical settings. Examples of registered uses for DDAC in these settings include application to indoor and outdoor hard surfaces ( e. g., walls, floors, tables, toilets, and fixtures), eating utensils, laundry, carpets, agricultural tools and vehicles, egg shells, shoes, milking equipment and udders, humidifiers, medical instruments, human remains, ultrasonic tanks, reverse osmosis units, and water storage tanks. There are also DDAC containing products that are used in residential and commercial swimming pools, in aquatic areas such as decorative ponds and decorative fountains, and in industrial process and water systems such as re circulating cooling water systems, drilling muds and packer fluids, oil well injection and wastewater systems. Additionally, DDAC containing products are used for wood preservation through nonpressure and pressure treatment methods. There are registered uses for fogging in occupational settings. Products containing DDAC are formulated as liquid ready to use, soluble concentrate, pressurized liquid, and water soluble packaging. The percentage of DDAC in the various end use products ranges from 0.08% to 80% DDAC. Residential products such as EPA Reg. No. 10324 69 range up to 50% DDAC for swimming pools and spas.

The durations and routes of exposure evaluated in this assessment include short term ( ST), intermediate term ( IT), and in some instances long term ( LT) inhalation exposures, ST dermal exposures, and ST oral exposures. The ST inhalation endpoint and the ST oral endpoint are based on a NOAEL of 10 mg/ kg/ day from a prenatal developmental toxicity study in rats. The LOAEL ( 20 mg/ kg/ day) was based largely on increased incidence of skeletal variations in females. This developmental study, along with a developmental study in rabbits do not indicate increased susceptibility in rats or rabbits from in utero and postnatal exposures to DDAC. The IT/ LT inhalation endpoint is also based on a NOAEL of 10 mg/ kg/ day but from a chronic toxicity study in dogs. No short term dermal endpoint for systemic effects was selected for DDAC, since no systemic effects were identified. However, a short term dermal irritation endpoint was identified. The short term dermal endpoint for the technical grade active ingredient ( TGAI) containing 80% ai diluted to 0.1% DDAC ( 2 mg/ kg/ day which is equivalent to 8 µ g/ cm2) was determined from a LOAEL of 6 mg/ kg/ day based on increased clinical and gross findings ( erythema, edema, exfoliation, excoriation, and ulceration). A 21 day dermal toxicity study was also conducted using a 0.13% ai formulation. No short term dermal endpoint was identified for this formulation because no irritation or systemic effects were identified up to and including the limit dose of 1,000 mg/ kg/ day. Intermediate or long term dermal irritation endpoints were not identified for DDAC. Because the effect to the skin is localized skin irritation, a skin concentration ( µ g/ cm2) of Page 4 of 52 exposure, rather then a dose ( mg/ kg/ day) was used to assess the dermal risk concerns. No body weight is needed for the dermal irritation endpoint, since no systemic dose is calculated. Since the toxicological endpoint for inhalation is female specific, a body weight of 60 kilograms is used in the assessment. This represents the body weight of an adult female. The Agency's level of concern ( LOC) for occupational and residential DDAC dermal, inhalation and oral exposures is 100 ( i. e., a margin of exposure ( MOE) less than 100 exceeds the Agency's level of concern). The level of concern is based on 10x for interspecies extrapolation and 10x for intraspecies extrapolation.

The acute toxicity categories ( Tox Cat) for DDAC include: acute oral ( Tox Category II), acute dermal ( Tox Category III), acute inhalation ( Tox Category I and primary eye and skin irritation ( Tox Category I). DDAC is not a dermal sensitizer.

Dietary Risk Summary DDAC can be used as a disinfectant or sanitizer on counter tops, utensils, appliances, tables, refrigerators, on animal premises and/ or farms, and in mushroom premises. The use of DDAC as an antimicrobial product on food or feed contact surfaces, agricultural commodities, and poultry premises including hatcheries and application to food grade eggs may result in pesticide residues in human food. Residues from treated surfaces, such as utensils, countertops, equipment, and appliances can migrate to food coming into contact with the treated and rinsed surfaces and can be ingested by humans.

The results of the indirect food contact ( i. e., countertops and utensils) assessment indicate no risks of concern. The acute and chronic dietary risks are the same because they are based on the same NOAEL. For indirect food contact exposures, the percent of the acute and chronic population adjusted dose occupied (% aPAD or cPAD) is 3.3 percent for adults and 13.3 percent for children. For direct applications to food, the % aPAD and cPAD for all individual uses and populations is less than or equal to 1. For the direct food contact as well as the indirect food contact the risks are not of concern. The drinking water exposures from DDAC uses are negligible and are not quantifiable.

Residential Risk Summary Dermal For the residential handler dermal exposure and risk assessment, dermal risks were calculated by comparing residues on the surface of the skin to the short term dermal irritation endpoints. Dermal residential handler exposures were not assessed for products containing less than 1% DDAC. Additional dermal toxicity studies could provide a better characterization of the relationship between percent DDAC in a formulation and dermal irritation. Residues on the surface of the skin ( dermal irritation exposure) were determined using hand unit exposures from CMA and/ or PHED adjusted for the surface area of the hand ( mg/ lb ai/ cm2), application rates, and use amounts. The dermal MOEs were above the target MOE of 100 for all scenarios except for the humidifier and swimming pool applications.

The residential post application dermal risks were assessed by comparing the surface residue on the skin ( dermal skin irritation exposure) to the short term dermal endpoint. It was assumed that during the exposure period the skin repeatedly contacts the treated surface until a steady state concentration of residues is achieved on the skin. For residential scenarios, the Page 5 of 52 post application dermal MOEs were above the target MOE of 100 for the laundered clothing ( assuming 1% residue transfer) but below the target MOE for the following:

  Wearing clothes treated with a fabric spray: ST dermal MOE = < 1 using both a 100% clothing to skin transfer factor and a 5% clothing to skin transfer factor.   Dermal contact on floors ( MOE = 33) and carpets ( MOE = 45).   There are no wipe data available to assess the children's dermal contact to treated decks and/ or play sets. Based on hand measurements of workers at the treatment plants, dermal risks may be of concern and therefore a wipe study is warranted.

Inhalation For the residential handler inhalation assessment, the inhalation risks were calculated by comparing the daily doses to the short term inhalation endpoint. The inhalation MOEs were above the target MOE of 100 for all scenarios.

For the residential post application inhalation exposure and risk assessment, the MOEs were below the target MOE of 100 for the following scenario:

  Humidifier: ST/ IT 8 hr Inhalation MOE = 27 for adults and 8 for children; ST/ IT 24 hr Inhalation MOE = 11 for adults and 5 for children Incidental Oral For the residential post application incidental oral assessment, the MOEs were above the target MOE of 100 for all scenarios except for mouthing of clothes treated with a fabric spray where the oral MOE = 12.

Aggregate Risk Summary The acute and chronic dietary aggregate risk assessment includes direct and indirect food contact uses. There are no drinking water exposures as a result of DDAC applications. The acute and chronic endpoints are based on the same NOAEL value. Based on the results of the acute and chronic aggregate assessment, the % aPAD and cPAD for adults and children are 3.8% and 14%, respectively. Therefore, the acute and chronic dietary aggregate risks are not of concern ( i. e., less then 100 % of aPAD and/ or cPAD).

The DDAC toxicity endpoints for the chronic dietary and the intermediate term incidental oral are based on the same toxic effect ( and same study), and therefore, these two dietary routes of exposure are aggregated. On the other hand, the dermal and inhalation routes of exposure are based on different toxic effects, and therefore, these two routes of exposure are not aggregated. However, the dermal route of exposure is aggregated among those dermal exposure scenarios that are believed to co occur. In addition, the inhalation route of exposure is also aggregated among the inhalation exposure scenarios that are believed to co occur. The aggregate risks are not of concern for adults for the oral and inhalation routes. However, the adult dermal MOE for the cleaning products are all of concern by themselves. As an aggregate, the adult dermal MOE is less than the target MOE of 100. For children, the oral aggregate ( dietary and intermediate term ingestion for children at day care centers) is 270. The children aggregate MOE for the dermal route is 42. No children aggregate inhalation scenarios were determined to co occur. It is important to note, however, that some of the individual risks for scenarios not included in the aggregate are of concern by Page 6 of 52 themselves ( e. g., the humidifier use and the fabric spray for clothing).

Occupational Risk Summary Dermal DDAC dermal irritation exposures and risks were not estimated for occupational handler exposures. Instead, dermal irritation exposures and risks will be mitigated using default personal protective equipment requirements based on the toxicity of the end use product. To minimize dermal exposures, the minimum PPE required for mixers, loaders, and others exposed to end use products containing concentrations of DDAC that result in classification of category I, II, or III for skin irritation potential will be long sleeve shirt, long pants, shoes, socks, chemical resistant gloves, and chemical resistant apron. Once diluted, if the concentration of DDAC in the diluted solution would result in classification of toxicity category IV for skin irritation potential, then the chemical resistant gloves and chemicalresistant apron can be eliminated for applicators and others exposed to the dilute. Note that chemical resistant eyewear will be required if the end use product is classified as category I or II for eye irritation potential.

Dermal irritation exposures are assumed to be negligible for all post application occupational scenarios, except those associated with wood preservation. As with occupational handlers, dermal irritation exposures and risks from post application activities in a wood preservation treatment facility will be mitigated using default personal protective equipment requirements based on the toxicity of the end use product. For construction workers handling treated wood the MOEs are potentially of concern. A wipe study on treated wood will be needed to assess the potential exposure to handling treated wood.

Inhalation For the occupational handler inhalation exposure and risk assessment, the MOEs were above the target MOE of 100 for all scenarios.

For the occupational inhalation post application exposure and risk assessment, the MOEs were above the target MOE of 100 for all scenarios except for fogging in a food processing plant. The 8 hr MOE from starting 2 hours after application ( i. e., 2 hour re entry interval) is 8.

Environmental Fate and Ecological Risk: AD Specific Uses The results of the dietary avian studies indicate that DDAC is practically non toxic to both mallard duck and bobwhite quail. In the Acute oral studies, the chemical was found to be moderately toxic to bobwhite quail. The results from freshwater fish acute toxicity studies demonstrated that DDAC was moderately to highly toxic. DDAC is very highly toxic to freshwater aquatic invertebrates. DDAC is very highly toxic to mysid shrimp a marine/ estuarine invertebrate. DDAC is toxic to freshwater alga at microgram concentrations. Data Gaps: The following data requirements are outstanding for the currently registered uses of DDAC: 850.4225  Non target plant phytotoxicity testing ( seedling emergence test using rice). 850.1035  Acute Sheepshead minnow testing Page 7 of 52 850.1300  Acute eastern oyster embryo larvae testing 850.1300  Chronic Daphnis magna testing Monitoring/ Tier II modeling of once through cooling tower use to establish EEC's for risk assessment.

Environmental Fate and Eco Risks: Agricultural Premises:

The Environmental Fate and Effects Division ( EFED) has evaluated the outdoor use of the quaternary ammonium compounds, didecyl ammonium chlorides ( DDAC), being considered for reregistration by the Antimicrobial Division ( AD) ( DP Barcode D325481). Although primarily used as antimicrobial agents, DDAC is labeled for use in puddles and decorative pools to control algae. This use is intended for waterbodies generally disconnected from the greater watershed and will not likely result in exposure to nontarget aquatic species. It is possible these uses will result in exposure to amphibians utilizing these waterbodies for some portion of their lifecycle ( e. g. reproduction) and to birds and mammals utilizing these waterbodies for drinking water. At the maximum label rate, 3 ppm initially followed by weekly 1.5 ppm treatments, there are no LOC exceedances, assuming the toxicity of DDAC is similar to that of ADBAC. However, due to the persistence of DDAC, it is possible that concentrations of DDAC in some waterbodies treated over time could become harmful to animals utilizing these waterbodies.

2.0 PHYSICAL AND CHEMICAL PROPERTIES The Group I Quat Cluster is a group of structurally similar quaternary ammonium compounds (" quats") that are characterized by having a positively charged nitrogen covalently bonded to two alkyl group substituents ( at least one C8 or longer) and two methyl substituents. In finished form, these quats are salts with the positively charged nitrogen ( cation) balanced by a negatively charged molecule ( anion). The anion for the quats in this cluster is chloride or bromide. In this document, the Group I Quat Cluster will be referred to as DDAC ( didecyl dimethyl ammonium chloride).

Currently, there are 4 active ingredients identified by the Agency that are registered and included in Case Number 3003. Table 2.1 below provides the common chemical name, active ingredient code, CAS number, chemical structure and number of registered product for each compound.

Table 2.1. Active Ingredients in the Group I Quat Cluster Identified by the AIJV Prod Code CAS RN Name Structure Chain Lengths 69149 7173 51 5 Didecyl Dimethyl Ammonium Chloride ( DDAC) N+

CH3 CH3 R Cl R R = C10 69166 5538 94 3 Dioctyl Dimethyl Ammonium Chloride N+

CH3 CH3 R Cl R R = C8 69165 32426 11 2 Octyl Decyl Dimethyl Ammonium Chloride N+

CH3 CH3 R1 Cl R2 R1 = C8 ( variable %) R2 = C10 ( variable %) Page 8 of 52 Table 2.1. Active Ingredients in the Group I Quat Cluster Identified by the AIJV Prod Code CAS RN Name Structure Chain Lengths 69146 84540 07 8 Alkyl Dimethyl Ethyl Ammonium Bromide N+

CH3 CH3 R Br H3C R = C12 ( 5%) C14 ( 90%) C16 ( 5%)

Table 2.2 provides the physical/ chemical characteristics that have been reported for DDAC.

Table2.2. Physical/ Chemical Properties of DDAC Parameter DDAC Molecular Weight 362.08 Density 0.9216 g/ cm3 at 25 C Boiling Point NA Water Solubility Completely soluble Vapor Pressure 2.33E 11 mmHg 3.0 ENVIRONMENTAL FATE DDAC is used primarily as a disinfectant, sanitizer, or as a microbiocide/ microbiostat. It also serves as an algaecide, bacteriocide/ bacteriostat, fungicide/ fungistat, insecticide, miticide, virucide, and tuberculocide. Use sites for DDAC include agricultural premises and equipment, food handling, commercial, industrial and institutional settings, residential areas or areas of public access, pets and kennels, medical facilities, swimming pools, aquatic areas, and industrial water systems. DDAC is also used as a wood preservative. As an agricultural pesticide, DDAC is used for ornamental plants, shrubs, and vines. Some of the required guideline studies for an environmental fate assessment have been submitted. The Agency is using these environmental fate studies for fate assessment of DDAC to fulfill the reregistration requirements.

DDAC has been shown to be hydrolytically stable under abiotic and buffered conditions over the pH 5 9 range. The calculated half lives for DDAC were 368 days at pH 5, 194 days at pH 7 ( TRIS), 175 days at pH 7 ( HEPES), and 506 days at pH 9. DDAC is stable to photodegradation in pH 7 buffered aqueous solutions; even in the presence of a photosensitizer ( acetone), degradation is minimal with a calculated half life of 227 days. DDAC is photolytically stable in soil with a calculated half life of 132 days.

Aquatic metabolism studies under aerobic and anaerobic conditions indicate that DDAC is stable to microbial degradation. The calculated aerobic and anaerobic half lives of 14C DDAC in flooded river water are 180 days and 261 days, respectively. Similarly, DDAC was found to be stable with very little degradation in aerobic soils during a year long metabolism study. The calculated half life for aerobic soil degradation was 1,048 days. However, a report on the biodegradability of DDAC prepared by the Registrant concluded that the degree of DDAC biodegradability is variable and is influenced by the chemical Page 9 of 52 concentration, alkyl chain length, the presence of anionic moieties and the quantity and characteristics of the microbial population. According to this report, DDAC is biodegradable and environmentally acceptable. This report was based on information from the open literature, unpublished sources, and meeting proceedings and has not been reviewed by the Agency.

DDAC is immobile in soil. A soil mobility study reviewed by the Agency shows that DDAC has a strong tendency to bind to sediment/ soil with Freundlich Kads values of 1,095, 8,179, 3,279, and 30,851 in sand, sandy loam, silty clay loam, and silt loam soils, respectively. Because of its strong adsorption to soils, DDAC is not expected to contaminate surface and ground waters.

Bioaccumulation of DDAC in freshwater fish is not likely to occur. Mean steady state bioconcentration factors for DDAC were determined to be 38X, 140X, and 81X in the edible, nonedible, and whole body fish tissue, respectively. During depuration, 57%, 67%, and 71% of the residues that accumulated in the edible, whole body, and nonedible tissues, respectively, were eliminated. DDAC is not expected to pose a concern for bioconcentration in aquatic organisms.

Information on the aqueous availability of DDAC from wood indicates that the use of DDAC as a wood preservative may result in minimal releases to the environment.

The Environmental Fate and Effects Division ( EFED) has evaluated the outdoor use of the quaternary ammonium compounds, didecyl ammonium chlorides ( DDAC), being considered for reregistration by the Antimicrobial Division ( AD) ( DP Barcode D325481). Although primarily used as antimicrobial agents, DDAC is labeled for use in puddles and decorative pools to control algae. This use is intended for waterbodies generally disconnected from the greater watershed and will not likely result in exposure to nontarget aquatic species. It is possible these uses will result in exposure to amphibians utilizing these waterbodies for some portion of their lifecycle ( e. g. reproduction) and to birds and mammals utilizing these waterbodies for drinking water. At the maximum label rate, 3 ppm initially followed by weekly 1.5 ppm treatments, there are no LOC exceedances, assuming the toxicity of DDAC is similar to that of ADBAC. However, due to the persistence of DDAC, it is possible that concentrations of DDAC in some waterbodies treated over time could become harmful to animals utilizing these waterbodies.

4.0 HAZARD CHARACTERIZATION 4.1 Hazard Profile DDAC was assigned a Toxicity Category II from results of two acute oral toxicity studies in rats, MRIDs 41394404 [ 65% a. i.; LD50 = 262 mg/ kg ( combined)] and 42296101 [ 80% a. i.; LD50 = 238 mg/ kg ( combined)]. DDAC was assigned Toxicity Category III from two acute dermal toxicity studies in rabbits, MRIDs 42053801 [ 65% a. i.; LD50 = 2930 mg/ kg ( combined)] and 00071158 [ 50% a. i.; LD50 = 4350 mg/ kg ( combined)]. For acute inhalation toxicity ( MRID 00145074; TRID 455201010), DDAC ( purity not reported) is assigned a Toxicity Category I ( LC50 = 0.07 mg/ L). For primary eye irritation, DDAC was found to be corrosive ( Toxicity Category I) in two primary eye irritation studies in rabbits, MRIDs Page 10 of 52 41394404 [ 65% a. i.] and 42161602 [ 80% a. i]. For primary dermal irritation, DDAC ( 80% a. i.) was found to be corrosive ( Toxicity Category I) in a primary dermal irritation study in rabbits ( MRID 42161601). For dermal sensitization, DDAC was found to be a non sensitizer in two dermal sensitization studies in guinea pigs ( MRID 42161603 [ 80% a. i.]) ( MRID 46367601 [ purity not reported]).

For subchronic toxicity, the database includes a 90 day oral toxicity test in rats ( MRID 40966302), a 90 day oral study in dogs ( MRID 40262901), and a 90 day dermal toxicity study in rats ( MRID 41305901). In the 90 day rat oral feeding study ( MRID 40966302), incidence of gross pathological observations and non neoplastic lesions, including a higher incidence of glycogen depletion in the liver and contracted spleens were observed. In the 90 day dog feeding study ( MRID 40269201), no treatment related clinical chemistry, hematology, urinalysis, or pathological findings were observed. In the 90 day dermal toxicity test in rats ( MRID 41305901), systemic toxicity was not observed and clinical and gross findings ( erythema, edema, exfoliation, excoriation and ulceration) were limited to the treated skins.

For developmental toxicity, the data from two developmental toxicity studies, one in the rat ( MRID 41886701, range finder MRID 42746901) and another in the rabbit ( MRID 41018701), do not indicate increased susceptibility in rats or rabbits from in utero and postnatal exposure to DDAC. In the rat developmental toxicity study ( MRID 41886701), developmental toxicity ( skeleton variations) was observed only at treatment levels which also resulted in maternal toxicity ( audible respiration). In the rabbit developmental toxicity study, developmental toxicity ( decreased fetal body weight and increased number of dead fetuses) occurred at levels which also resulted in maternal toxicity ( hypo activity, audible respiration, and decreased body weight gain).

For reproductive toxicity, the toxicity database for DDAC includes a 2 generational reproductive toxicity study in rats ( MRID 41804501). In this study, effects in offspring ( decreased pup body weight/ weight gain) occurred at the same dose level as maternal effects ( decreased maternal body weight/ weight gain and food consumption).

In a 1 year dog feeding study ( MRID 41970401), beagle dogs were given doses of 0, 3, 10, or 20/ 30 mg/ kg/ day in the diet. Treatment related clinical signs ( soft/ mucoid feces, emesis) were observed frequently in high dose animals, and total cholesterol levels were significantly decreased in high dose females.

DDAC was not carcinogenic when administered in the diet in 2 year chronic/ carcinogenicity studies in rats ( MRID 41965101) and mice ( MRID 41802301). In the rat study, an increase in incidence of interstitial cell adenomas in the testes were reported, but the incidence was with in the range of historical controls. In the mouse study, no treatmentrelated effects were noted in the incidence of clinical signs, deaths, and gross and histopathological observations.

For mutagenicity, DDAC was negative in a battery of tests. In the Ames test ( MRID 40282201, supplemental information MRID 44005801); DDAC was not mutagenic with or without metabolic activation. In a forward gene mutation test ( MRID 93014008, reformat of 40895202), DDAC was negative for induction of gene mutations in CHO cells at the HGPRT locus with and without metabolic activation. In an in vitro chromosome aberration test Page 11 of 52 ( MRID 41252601), DDAC did not induce chromosome aberration in the Chinese hamster ovary ( CHO) cells with or without metabolic activation. In an unscheduled DNA synthesis ( UDS) assay ( MRID 93014007, reformat of 40895201), DDAC did not cause UDS in primary rat hepatocytes.

Although there are no neurotoxicity studies available in the database, the available toxicity for DDAC show no evidence for neurotoxic effects.

In a rat pharmacokinetics/ metabolism study ( MRID 41617101 and addendum MRID 41385101), single oral doses of 14C DDAC ( 5 or 50 mg/ kg) or repeated doses ( 34 ppm of DDAC in the diet for 14 days and then one single dose of 5 mg/ kg of 14C DDAC) were given to both male and female rats. DDAC was mostly excreted in the feces within 3 days principally as parent compound and metabolites. The elimination pattern and metabolic profile was not substantially altered by the dose or exposure duration. Male and female rats showed similar elimination patterns, but females metabolized DDAC more extensively than males. Four major metabolites were identified as oxidation products with oxidation confined to the decyl side chains.

The acute toxicity data for DDAC are summarized below in Table 4.1 ( USEPA, 2006).

Table 4.1 Acute Toxicity Data for DDAC Guideline No. Study Type MRID #( S). Results Toxicity Category 81 1 Acute Oral 42296101 41394404 LD50 ( combined) = 238 mg/ kg LD50 ( combined) = 262 mg/ kg II 81 2 Acute Dermal 42053801 LD50 (   ) = 3140mg/ kg; LD50 (   ) = 2730mg/ kg; LD50 ( combined) = 2930 mg/ kg III 81 3 Acute Inhalation 00145074 LC50 = 0.07mg/ L I 81 4 Primary Eye Irritation 42161602 41394404 Severe eye irritant I 81 5 Primary Skin Irritation 42160601 Severe dermal irritant I 81 6 Dermal Sensitization 46367601 Not a sensitizer Page 12 of 52 4.2 FQPA Considerations Under the Food Quality Protection Act ( FQPA), P. L. 104 170, which was promulgated in 1996 as an amendment to the Federal Insecticide, Fungicide, and Rodenticide Act ( FIFRA) and the Federal Food, Drug and Cosmetic Act ( FFDCA), the Agency was directed to " ensure that there is a reasonable certainty that no harm will result to infants and children" from aggregate exposure to a pesticide chemical residue. The law further states that in the case of threshold effects, for purposes of providing this reasonable certainty of no harm, " an additional tenfold margin of safety for the pesticide chemical residue and other sources of exposure shall be applied for infants and children to take into account potential pre and postnatal toxicity and completeness of the data with respect to exposure and toxicity to infants and children. Notwithstanding such requirement for an additional margin of safety, the Administrator may use a different margin of safety for the pesticide residue only if, on the basis of reliable data, such margin will be safe for infants and children."

The Agency ( USEPA, 2006) has decided that the FQPA safety factor be removed for DDAC, based upon the existence of a complete developmental and reproductive toxicity database and the lack of evidence for increased susceptibility in these data.

4.3 Dose Response Assessment Table 4.2 summarizes the toxicological endpoints for DDAC ( USEPA, 2006).

Table 4.2 Summary of Toxicological Endpoints for DDAC Exposure Scenario Dose Used in Risk Assessment ( mg/ kg/ day) Target MOE/ UF, Special FQPA SF for Risk Assessment Study and Toxicological Effects NOAEL( developmental) = 10 mg/ kg/ day FQPA SF = 1 UF = 100 ( 10x inter species extrapolation, 10x intra species variation) Prenatal Developmental Toxicity  Rat MRID 41886701 LOAEL = 20 mg/ kg/ day based on increased incidence of skeletal variations. Acute Dietary ( Females 13 50)

Acute RfD = 0.1 mg/ kg/ day ( for Females age 13 50)

Acute Dietary ( general population) An acute dietary endpoint was not identified in the data base. This risk assessment is not required NOAEL = 10 mg/ kg/ day FQPA SF = 1 UF = 100 ( 10x inter species extrapolation, 10x intra species variation Chronic Toxicity Study  Dog MRID 41970401 LOAEL = 20 mg/ kg/ day based on increased incidence of clinical signs in males and females and decreased total cholesterol levels in females. Chronic Dietary ( general population)

Chronic RfD = 0.1 mg/ kg/ day Non Dietary Exposures Page 13 of 52 Table 4.2 Summary of Toxicological Endpoints for DDAC Exposure Scenario Dose Used in Risk Assessment ( mg/ kg/ day) Target MOE/ UF, Special FQPA SF for Risk Assessment Study and Toxicological Effects Incidental Oral Short Term NOAEL ( developmental) = 10 mg/ kg/ day Target MOE = 100 ( 10x interspecies extrapolation, 10x intraspecies variation) FQPA SF = 1 Prenatal Developmental Toxicity  Rat MRID 41886701 LOAEL = 20 mg/ kg/ day based on increased incidence of skeletal variations.

Incidental Oral Intermediate Term NOAEL = 10 mg/ kg/ day Target MOE = 100 ( 10x interspecies extrapolation, 10x intraspecies variation) FQPA SF = 1 Chronic Toxicity Study  Dog MRID 41970401 LOAEL = 20 mg/ kg/ day based on increased incidence of clinical signs in males and females and decreased total cholesterol levels in females.

Dermal, Short term ( formulated product, 0.13% a. i.) No endpoint identified. No dermal or systemic effects identified in the 21 day dermal toxicity study ( MRID 45656601) up to and including the limit dose of 1000 mg/ kg/ day Dermal, Short term ( TGAI 80% diluted to 0.1%) NOAEL( dermal) = 2 mg/ kg/ day ( 8 µ g/ cm2) b Target MOE = 100 ( 10x interspecies extrapolation, 10x intraspecies variation) 90 day Dermal Toxicity  Rat MRID 41305901 LOAEL = 6 mg/ kg/ day based on increased clinical and gross findings ( erythema, edema, exfoliation, excoriation, and ulceration)

Dermal, Intermediateand Long term ( formulated product) No appropriate endpoint identified.

Inhalation, Short Term NOAEL b = 10 mg/ kg/ day Target MOE = 100 ( 10x interspecies extrapolation, 10x intraspecies variation) FQPA SF = 1 Prenatal Developmental Toxicity  Rat MRID 41886701 LOAEL = 20 mg/ kg/ day based on increased incidence of skeletal variations.

Inhalation, Intermediate and Long Term NOAEL c = 10 mg/ kg/ day Target MOE = 100 ( 10x interspecies extrapolation, 10x intraspecies variation) FQPA SF = 1 Chronic Toxicity Study  Dog MRID 41970401 LOAEL = 20 mg/ kg/ day based on decreased total cholesterol levels in females.

UF = uncertainty factor, FQPA SF = special FQPA safety factor, NOAEL = no observed adverse effect level, LOAEL = lowest observed adverse effect level, PAD = population adjusted dose ( a = acute, c = chronic), RfD = reference dose, MOE = margin of exposure, LOC = Level of concern, NA = Not Applicable. ashort term dermal endpoint = ( 2 mg/ kg rat x 0.2 kg rat x 1000 ug/ mg) / 50cm2 area of rat dosed = 8 µ g/ cm2 . b an additional UF of 10x is used for route extrapolation from an oral endpoint to determine if a confirmatory study is warranted.

4.4 Endocrine Disruption Page 14 of 52 EPA is required under the FFDCA, as amended by FQPA, to develop a screening program to determine whether certain substances ( including all pesticide active and other ingredients) " may have an effect in humans that is similar to an effect produced by a naturally occurring estrogen, or other such endocrine effects as the Administrator may designate." Following recommendations of its Endocrine Disruptor and Testing Advisory Committee ( EDSTAC), EPA determined that there was a scientific basis for including, as part of the program, the androgen and thyroid hormone systems, in addition to the estrogen hormone system. EPA also adopted EDSTAC's recommendation that the Program include evaluations of potential effects in wildlife. For pesticide chemicals, EPA will use FIFRA and, to the extent that effects in wildlife may help determine whether a substance may have an effect in humans, FFDCA authority to require the wildlife evaluations. As the science develops and resources allow, screening of additional hormone systems may be added to the Endocrine Disruptor Screening Program ( EDSP).

5.0 EXPOSURE ASSESSMENT AND CHARACTERIZATION 5.1 Summary of Registered Uses For dietary uses, DDAC can be used as a disinfectant or sanitizer on counter tops, utensils, appliances, tables, refrigerators, on animal premises and/ or farms, and in mushroom premises. The use of DDAC as an antimicrobial product on food or feed contact surfaces, agricultural commodities, and poultry premises including hatcheries and application to foodgrade eggs may result in pesticide residues in human food. Residues from treated surfaces, such as utensils, countertops, equipment, and appliances can migrate to food coming into contact with the treated and rinsed surfaces and can be ingested by humans.

Products containing DDAC can be used as general cleaners, disinfectants, and deodorizers. These products are primarily for use on indoor surfaces such as hard floors, carpets, walls, bathroom fixtures, trash cans, toilet bowls, and household contents. Additionally, other uses in the home include liquid laundry deodorizers that are added to the final rinse of the wash cycle, algaecide/ bactericides that are added to portable humidifiers and swimming pools, and deodorizers that are sprayed on fabric. Residents may also be exposed to items that have been treated with DDAC in occupational settings, such as dimensional lumber for decks and play sets. Appendix A presents a summary of all exposure scenarios that may occur in residential settings based on examination of product labels.

The non antimicrobial uses of DDAC are assessed separately by the Health Effects Division ( DP Barcode: D 326896).

5.2 Dietary Exposure and Risk In the absence of data on DDAC residues on treated food contact surfaces, the Agency estimated residue levels that may occur in food from the application rates on food contact surfaces. Dietary exposures from poultry hatcheries, mushroom houses and hydroponic uses are expected to be much lower than the dietary exposures resulting from the surface disinfectant and sanitizing uses; therefore, these uses were not assessed separately.

To estimate the Estimated Daily Intake ( EDI) to treated food contact surfaces and Page 15 of 52 food utensils, an FDA ( FDA, 2003) model was used in lieu of residue data. The maximum application rate for DDAC in food handling establishments from the various labeled ready touse products is 0.0043 pounds per gallon of treatment solution. The EDI calculations presented in this assessment assumes that food can contact 2,000 cm2 or 4,000 cm2 ( 50% and 100% of the FDA worst case scenario) of treated surfaces, and that 10% of the pesticide migrate to food. The use of the 10% transfer rate, instead of the use of a 100% transfer rate that is used in the FDA Sanitizer Solution Guidelines, requires the submission of confirmatory data to establish the reliability of the use of the10% transfer rate. These daily estimates were conservatively used to assess both acute and chronic dietary risks. None of the calculated percent acute population adjusted dose (% aPAD) or chronic (% cPAD) estimates exceeded 100%. The estimated EDI, % aPAD, and % cPAD for food contact surfaces are presented in Table 5.1. Note: The NOAEL for both the acute and chronic dietary endpoints are the same so only one % PAD is reported ( i. e., aPAD and cPAD are identical). The results indicate that for the aggregate risks the adult % aPAD and % cPAD is 2.8% for males and 3.3% for females, and for children 13.3%.

For DDAC treatments of food processing plants, the application rates are similar to food handling establishments presented in Table 5.1, and hence the exposure, EDIs, DDDs, and % aPAD and cPADs are also similar.

Table 5.1: Calculated EDIs, aPAD, and cPAD for Utensils and Countertops Utensils Countertops Aggregate Exposure Group EDI ( mg/ day) DDD ( mg/ kg/ d) % PADa EDI ( mg/ day) DDD ( mg/ kg/ d) % PADa EDI ( mg/ p/ d) DDD ( mg/ kg/ d) % PADa ( mg/ kg/ d)

Adult males 0.0959 0.00137 1.37 0.103 0.00147 1.47 0.199 0.00284 2.84 Adult females 0.0959 0.00160 1.60 0.103 0.00172 1.72 0.199 0.00332 3.32 Children 0.0959 0.00639 6.39 0.103 0.00687 6.87 0.199 0.0133 13.3 a. % PAD = exposure ( DDD) /( aPAD or cPAD) x 100. The acute and chronic population average dose is the same; therefore the % PADs are the same. EDI is the estimated daily intake ( mg/ day). DDD is the dietary daily dose ( mg/ kg/ day).

The maximum application rate for DDAC for bottling/ packing of food is 0.0020 lbs a. i per gallons of treatment solution. EDI values were calculated using an approach similar to that used for treated food contact surfaces and food utensils. Exposure was assumed to occur through the ingestion of three food products that might be packaged with treated material: milk, egg products, and beverages ( alcoholic and non alcoholic). The calculated % aPAD and % cPAD did not exceed 100%. The results of the EDI and % cPAD are presented in Table %. 2. Page 16 of 52 Table 5.2: Calculated EDIs, aPAD, and cPAD for Representative Dairy and Beverage Consumption Food Type Exposure Group EDI ( mg/ p/ d) DDD ( mg/ kg/ d) % PAD ( aPAD & cPAD)

Adult Male 6.44x10 5 0.0644 Adult Female 0.00451 7.52x10 5 0.0752 Milk Childa 0.00290 1.94x10 4 0.194 Adult Male 1.16x10 10 1.16x10 7 Adult Female 8.10x10 9 1.35x10 10 1.35x10 7 Egg product Child a 5.22x10 9 3.48x10 10 3.48x10 7 Adult Male 3.29x10 4 0.329 Adult Female 0.0230 3.84x10 4 0.384 Beverages, non alcoholic Childa 0.0148 9.90x10 4 0.990 Adult Male 4.16x10 6 0.00416 Beverages, alcoholic, beer Adult Female 2.91x10 4 4.85x10 6 0.00485 5.3 Drinking Water Exposures and Risks The only DDAC outdoor uses are as an algaecide in decorative pools and for oil field operations which are considered to be contained. Therefore, the DDAC contributions to drinking water exposure are considered to be negligible and are not quantified.

5.4 Residential Exposure/ Risk Pathway The exposure scenarios assessed in this document for the representative antimicrobial uses selected by the Agency to represent the residential risks include:

  Indoor hard surfaces ( e. g., mopping, wiping, trigger pump sprays);   Carpets;   Swimming pools;   Wood preservative;   Textiles ( e. g., diapers treated during washing and clothes treated with fabric spray); and   Humidifiers.

Exposure Data and Assumptions The residential handler scenarios were assessed to determine dermal and inhalation exposures. The scenarios were assessed using PHED and CMA data. Specific surrogate data used in determining the dermal and inhalation exposures are reported below:

$ For the mopping, wiping, low pressure hand wand, and liquid pour in swimming pool the CMA data were used; and $ For aerosol spray and trigger pump scenarios the PHED data were used.

The quantities handled/ treated were estimated based on information from various sources, including the Antimicrobial Division's estimates. Page 17 of 52 $ For mopping scenarios, it is assumed that 1 gallon of diluted solution is used.

$ For wiping and trigger pump spray scenarios, it is assumed that 0.5 liter ( 0.13 gal) of diluted solution is used.

$ For low pressure hand wand, it was assumed that 2 gallons are used in all indoor applications.

$ For liquid pour in swimming pool scenario, it was assumed that a residential pool contains 20,000 gallons of water.

$ For liquid pour in humidifier scenario, it was assumed that a humidifier with a 11 gallon tank would be treated, based on Holmes Model# HM4600 U 11. This humidifier releases 11 gallons/ 1,700 ft2/ 24 hours ( http:// www. holmesproducts. com/ estore/ product. aspx? CatalogId= 3& CategoryId= 112 0& ProductId= 582).

Post application scenarios have been developed that encompass multiple products, but still represent a high end exposure scenario for all products represented. Post application scenarios assessed include crawling on treated hard surfaces, carpets, and treated lumber such as decks/ play sets ( dermal and incidental oral exposure to children), wearing treated clothing from wash treatment and from a direct clothing spray treatment ( dermal exposure to adults and children and incidental oral exposure to children), using portable humidifiers ( adult and child inhalation exposure), and swimming in treated pools ( adult and child incidental ingestion).

Since no toxicological endpoint of concern was identified for dermal systemic adverse effects, post application dermal risks were assessed using the toxicological endpoint of concern for dermal irritation. Note: Products containing less then 1 percent were not assessed as no dermal endpoint was identified. The residential post application dermal risks were assessed by comparing the surface residue on the skin ( dermal skin irritation exposure) to the short term dermal irritation endpoint. It was assumed that during the exposure period, the skin repeatedly contacts the treated surface until a steady state concentration of residues is achieved on the skin.

The duration of exposure for most homeowner exposures is believed to be best represented by the short term duration ( 1 to 30 days). The reason that short term duration was chosen to be assessed is because the different handler and post application scenarios are assumed to be episodic, not daily. In addition, homeowners are assumed to use different products with varying activities, not exclusively DDAC treated products.

Risk Characterization A summary of the residential handler inhalation risks are presented in Table 5.3. Although the inhalation endpoint represents short, intermediate, and long term durations, the exposure duration of most homeowner applications of cleaning products is believed to be best represented by the short term duration. The inhalation toxicological endpoint is based on an oral study because a route specific inhalation study is not available. The calculated inhalation MOEs are above the target MOE of 100. The dermal MOEs are presented in Table 5.4. The dermal MOEs were below the target MOE of 100 for all scenarios evaluated except for applications to humidifiers and swimming pools . Page 18 of 52 Table 5.3 Short Term Residential Handler Inhalation Exposures and MOEs Exposure Scenario Application Method Application Method Application Ratea ( lb ai/ gallon) Quantity Handled/ Treated per dayb ( gallons) Unit Exposure ( mg/ lb a. i.) Daily Dose ( mg/ kg/ day) c MOE d ( Target MOE = 100)

Mopping 0.020 1 2.38 0.00079 13,000 Wiping 0.020 0.13 67.3 0.0029 3,400 Application to indoor hard surfaces Trigger Spray 0.020 0.13 2.4 0.00010 96,000 Application to Carpets Low Pressure Spray 0.0088 2 0.681 0.012 50,000 Application to Swimming Pools Liquid Pour 0.0000244 20,000 0.00346 0.00002 510,000 Application to Humidifiers Liquid Pour 0.0043 11 1.89 0.0015 6,700 a Application rates are the maximum application rates determined from EPA registered labels for DDAC. b Amount handled per day values are estimates or label instructions. c Daily dose ( mg/ kg/ day) = [ unit exposure ( mg/ lb a. i.) x application rate ( lb ai/ gal) x quantity treated ( gal/ day) x absorption factor ( 1.0 for inhalation)]/ Body weight ( 60 kg for inhalation). d MOE = NOAEL / Absorbed Daily Dose. [ Where short term NOAEL = 10 mg/ kg/ day for inhalation]. Target MOE = 100.

Table 5.4 Short Term Residential Handler Dermal Risks Exposure Scenario Application Method Application Ratea ( lb ai/ gal) Quantity Handled/ Treated per dayb ( gallon) Hand Unit Exposure Adjusted for Surface Area ( mg/ lb ai/ cm2) c Dermal Skin Irritation Exposure d (: g/ cm2) MOE e ( Target MOE = 100)

Products with < 1% DDAC No dermal endpoint identified for products with < 1% DDAC Products with 1 to 10% DDAC ( NOAEL= 8 µ g/ cm3)

Mopping 0.0043 1 0.063 0.273 29 Wiping 0.0043 0.13 1.341 0.750 11 Application to indoor hard surfaces Trigger Spray 0.0043 0.13 0.129 0.072 110 Application to Carpets Low Pressure Spray 0.0088 2 0.161 2.832 3 Humidifier Liquid Pour 0.0043 11 0.000239 0.011 710 Application to swimming pools Liquid Pour 0.000017 20,000 0.000239 0.080 98 Products with > 10% DDAC ( NOAEL= 8 µ g/ cm3)

Mopping 0.020 1 0.063 1.27 6 Wiping 0.020 0.13 1.341 3.49 2 Application to indoor hard surfaces Trigger Spray 0.020 0.13 0.129 0.34 24 Application to Carpets Low Pressure Spray 0.0085 2 0.161 2.731 3 Application to swimming pools Liquid Pour 0.000017 20,000 0.000239 0.08 98 a Application rates are the maximum application rates determined from EPA registered labels for DDAC. b Amount handled per day values are estimates or label instructions. c Unit Exposure ( mg/ lb ai/ cm2) = Hand unit exposure from PHED or CMA ( mg/ lb ai) / surface area of hand ( 820 cm2). d Dermal Skin Irritation Exposure (: g/ lb ai/ cm2) = Unit Exposure ( mg/ lb ai/ cm2) x Application Rate ( lb ai/ gal) x Quantity Treated ( gal/ day) x 1,000 : g/ mg e MOE = NOAEL (: g/ cm2)/ Dermal Skin Irritation Exposure (: g/ cm2). [ Where short term dermal NOAEL = 8 µ g/ cm2. Target MOE = 100. Page 19 of 52 A summary of the residential post application are presented in Table 5.5. Although the inhalation endpoint represents short, intermediate, and long term durations, the exposure duration of most homeowner applications of cleaning products is believed to be best represented by the short term duration. The inhalation toxicological endpoint is based on an oral study because a route specific inhalation study is not available. The calculated incidental oral MOEs are above the target MOE of 100. The dermal MOEs are below the target MOE for all scenarios except for the laundered clothing. The inhalation MOEs are above the target MOE of 100 for all scenarios, except the humidifier. The 24 hour inhalation MOEs for adults and children are 10 and 4, respectively.

Table 5.5. Short term Residential Post Application Risks for Adults and Children. Exposure Scenario Dermal MOE Incidental Ingestion MOE Inhalation MOE Child playing on floor 33 760 NA Child playing on carpet 45 520 NA Clothing ( Laundered   1% transfer) 690 adults and children 2,600 NA Clothing ( Fabric spray   5% transfer) 1 12 6 average Child playing on decks/ play sets 3 max 360 NA Swimming NA Ranges from 330 to 4,000 for adults and children NA Adult 11 ( 24 hrs) Humidifiers NA NA Child 5 ( 24 hrs) NA = not assessed because negligible exposure is assumed by that route for the exposure scenario of concern. Page 20 of 52 6.0 AGGREGATE RISK ASSESSMENT AND RISK CHARACTERIZATION In order for a pesticide registration to continue, it must be shown that the use does not result in " unreasonable adverse effects on the environment". Section 2 ( bb) of FIFRA defines this term to include " a human dietary risk from residues that result from a use of a pesticide in or on any food inconsistent with standard under section 408..." of FFDCA. Consequently, even though no pesticide tolerances have been established for DDAC, the standards of FQPA must still be met, including " that there is reasonable certainty that no harm will result from aggregate exposure to pesticide chemical residue, including all anticipated dietary exposures and other exposures for which there are reliable information." Aggregate exposure is the total exposure to a single chemical ( or its residues) that may occur from dietary ( i. e., food and drinking water), residential, and other non occupational sources, and from all known or plausible exposure routes ( oral, dermal, and inhalation). Aggregate risk assessment were conducted for short term ( 1 30 days), intermediate term ( 1 6 months) and chronic ( several months to lifetime) exposures.

In performing aggregate exposure and risk assessments, the Office of Pesticide Programs has published guidance outlining the necessary steps to perform such assessments ( General Principles for Performing Aggregate Exposure and Risk Assessments, November 28, 2001; available at http:// www. epa. gov/ pesticides/ trac/ science/ aggregate. pdf). Steps for deciding whether to perform aggregate exposure and risk assessments are listed, which include: identification of toxicological endpoints for each exposure route and duration; identification of potential exposures for each pathway ( food, water, and/ or residential); reconciliation of durations and pathways of exposure with durations and pathways of health effects; determination of which possible residential exposure scenarios are likely to occur together within a given time frame; determination of magnitude and duration of exposure for all exposure combinations; determination of the appropriate technique ( deterministic or probabilistic) for exposure assessment; and determination of the appropriate risk metric to estimate aggregate risk.

6.1 Acute and Chronic Aggregate Risks The acute and chronic aggregate risk assessment includes dietary and drinking water exposures. No drinking water exposures were identified for DDAC. Acute and chronic dietary risk estimates from direct and indirect food uses are presented in Section 5.2. Table 6 1 presents a summary of these exposures, including the aggregate indirect and direct dietary exposure ( all direct and indirect food contact exposures). Based on the results of the acute and chronic aggregate assessment, the % aPAD and % cPAD for adults and children are 3.8% and 14%, respectively. Therefore, the acute and chronic dietary risks are not of concern ( i. e., less then 100 % of aPAD and cPAD). Page 21 of 52 Table 6 1. DDAC Acute and Chronic Aggregate Exposures and Risks ( aPAD and cPAD)

Acute and Chronic Dietary Exposures ( mg/ kg/ day)

Exposure Routes Indirect Dietary Exposuresa Direct Food Contact Dietary Exposuresa Drinking Water Exposures Aggregate Dietary Exposuresb % aPAD and cPAD ( MOE)

Adults Oral Ingestion 0.0033 0.00046 None 0.00376 3.8 ( 2,700) Children Oral Ingestion 0.013 0.0012 None 0.0142 14 ( 700) a Dietary ( indirect + direct food contact) exposures are presented in Tables 5.1 and 5.2. b Aggregate Dietary Exposures = indirect dietary + direct food contact + drinking water exposures. c % aPAD and cPAD ( percent acute or chronic population adjusted dose) = aggregate exposures / ( a PAD or cPAD) x 100. Where aPAD and cPAD = NOAEL 10 mg/ kg/ day / 100x uncertainty factor = 0.1 mg/ kg/ day. MOE = NOAEL of 10 mg/ kg/ day / aggregate dietary exposures mg/ kg/ day.

6.2 Short and Intermediate Term Aggregate Exposures and Risks Short and intermediate term aggregate exposures and risks were assessed for adults and children that could be exposed to DDAC residues from the use of products in nonoccupational environments. The short and intermediate term aggregate risks account for pesticide exposures from the diet, drinking water, and residential uses. The following list summarizes all of the potential sources of DDAC exposures for adults and children.

Adult DDAC exposure sources:

handling of cleaning products containing DDAC as an active ingredient during wiping, mopping, and spraying activities;

applying products containing DDAC to lawns/ ornamentals;

applying DDAC as an air deodorizer using an aerosol spray;

applying DDAC to carpets using a low pressure sprayer;

applying DDAC to swimming pools via open pouring;

applying DDAC to humidifiers via open pouring;

contacting pressure treated wood;

wearing treated clothing;

use of DDAC in humidifiers; and

eating food having DDAC residues from indirect or direct food contact.

Child DDAC exposure sources:

post application exposures to cleaning product residues containing DDAC that are used on hard surfaces ( e. g, floors/ carpets);

breathing air treated with a humidifier;

swimming in treated pools;

contacting pressure treated wood;

wearing treated clothing/ diapers;

eating food having DDAC residues from indirect or direct food contact.

The use patterns of the products and probability of co occurrence must be considered Page 22 of 52 when selecting scenarios for incorporation in the aggregate assessment. Table 6 2 summarizes the scenarios included in the short and intermediate term aggregate assessments.

Table 6 2. Exposure Scenarios Included in the Aggregate Assessments Short term ( ST) Aggregate Intermediate Term ( IT) Aggregate Adults

chronic dietary ( direct and indirect)

handling cleaning products ( wipe + trigger pump spray)

wearing treated clothing

humidifier Oral: ST and IT endpoints are the same for both durations.

Dermal: ST endpoint only.

Inhalation: All durations same endpoint.

Children

chronic dietary   ( direct and indirect)

post application to cleaning product on carpets ( dermal and oral)

wearing treated clothing

humidifier Oral: ST and IT endpoints are the same for both durations.

Dermal: ST endpoint only.

Inhalation: All durations same endpoint.

The chronic dietary exposures were used in both the short and intermediate term aggregate assessment because chronic dietary exposures occur nearly every day ( as opposed to acute dietary exposures occurring on a one time basis). Therefore, short or intermediateterm non dietary exposures have a much higher probability to co occur with the chronic dietary intake.

Cleaning activities in a residential setting occur on a short term basis. However, the DDAC containing cleaning products are also labeled for use in institutional settings such as day care facilities where cleaning activities can occur on an intermediate term basis. Therefore, children could have exposure to cleaning product residues on a more continuous basis in a day care facility, thus, these post application scenarios were included in the intermediate term aggregate assessment.

The DDAC toxicity endpoints for the chronic dietary and the intermediate term incidental oral are based on the same toxic effect ( and same study), and therefore, these two dietary routes of exposure are aggregated. On the other hand, the dermal and inhalation routes of exposure are based on different toxic effects, and therefore, these two routes of exposure are not aggregated. However, the dermal route of exposure is aggregated among those dermal exposure scenarios that are believed to co occur. In addition, the inhalation route of exposure is also aggregated among the inhalation exposure scenarios that are believed to co occur. Aggregate risks were calculated using the total MOE approach outlined in OPP guidance for aggregate risk assessment ( August 1, 1999, Updated " Interim Guidance for Incorporating Drinking Water Exposure into Aggregate Risk Assessments"). Table 6 3 presents a summary of the short term aggregate risks ( i. e., MOEs). Only the short term aggregate is presented because the endpoints for incidental oral as well as inhalation are identical for the short and intermediate term durations. Only a short term dermal endpoint was identified ( i. e., no intermediate and/ or long term dermal endpoints were identified).

The aggregate risks are not of concern for adults for any of the three routes of exposure except for the dermal exposure. The adult dermal MOE for the cleaning products indicate that the MOEs are less than the target MOE of 100. For children, the oral aggregate Page 23 of 52 ( dietary and intermediate term ingestion for children at day care centers) is 270. The children aggregate MOE for the dermal route is 42. No children aggregate inhalation scenarios were determined to co occur. It is important to note, however, that some of the individual risks for scenarios not included in the aggregate are of concern by themselves ( e. g., the humidifier use and the fabric spray for clothing).

Table 6 3. Short and Intermediate term Aggregate Risk ( MOE) Assessment for DDAC Exposure Routes Chronic Dietary MOE Cleaning Product MOEs ( Adult Applicators & Children Playing) Humidifier MOE Wearing Treated Clothing MOE Route Specific Aggregate MOE Adults Oral Ingestion 2,700 NA NA NA 2,700 Dermal ( 1 to 10% ai) 29 ( mop) 11 ( wipe) 110 ( spray) 7 Dermal (> 10% ai) NA 3 ( mop) 1 ( wipe) 12 ( spray) NA 690 1 Inhalation NA 13,000 ( mop) 3,400 ( wipe) 96,000 ( spray) Not included, risk of concern NA 2,600 Children Oral Ingestion 700 520 ( IT hand to mouth carpets) NA 2,600 ( IT Laundered) 270 Dermal NA 45 ( playing on carpets, 5% residue transfer) NA 690 ( Laundered) 42 Inhalation NA NA Not included, risk of concern NA No cooccurrence Aggregate MOE = 1/(( 1/ MOEsame route) + ( 1/ MOE same route) + etc)

7.0 CUMULATIVE EXPOSURE AND RISK Another standard of section 408 of the FFDCA which must be considered in making an unreasonable adverse effect determination is that the Agency considers " available information" concerning the cumulative effects of a particular pesticide's residues and " other substances that have a common mechanism of toxicity."

Unlike other pesticides for which EPA has followed a cumulative risk approach based on a common mechanism of toxicity, EPA has not made a common mechanism of toxicity finding as to DDAC and any other substances and DDAC does not appear to produce a toxic metabolite produced by other substances. For the purposes of this tolerance action, therefore, EPA has not assumed that DDACs has a common mechanism of toxicity with other substances. For information regarding EPA's efforts to determine which chemicals have a common mechanism of toxicity and to evaluate the cumulative effects of such chemicals, see the policy statements released by EPA's Office of Pesticide Programs concerning common mechanism determinations and procedures for cumulating effects from substances found to have a common mechanism on EPA's website at http:// www. epa. gov/ pesticides/ cumulative/. Page 24 of 52 8.0 OCCUPATIONAL EXPOSURE ASSESSMENT Potential occupational handler exposure can occur in various use sites, which include: agricultural premises, industrial processes and water systems, food handling premises, commercial/ institutional/ industrial premises, medical premises, swimming pools, and aquatic areas. Additionally, occupational exposure can occur during the preservation of wood. For the preservation of wood, the procedure for treatment can occur in different ways, such that multiple worker functions were analyzed. Due to the complexity of the wood preservative analysis, the results for handler and post application exposures are presented separately in Section 8.3.

8.1 Occupational Handler Exposures DDAC dermal irritation exposures and risks were not estimated for occupational handler exposures. Instead, dermal irritation exposures and risks will be mitigated using default personal protective equipment requirements based on the toxicity of the end use product. To minimize dermal exposures, the minimum PPE required for mixers, loaders, and others exposed to end use products containing concentrations of DDAC that result in classification of category I, II, or III for skin irritation potential will be long sleeve shirt, long pants, shoes, socks, chemical resistant gloves, and chemical resistant apron. Once diluted, if the concentration of DDAC in the diluted solution would result in classification of toxicity category IV for skin irritation potential, then the chemical resistant gloves and chemicalresistant apron can be eliminated for applicators and others exposed to the dilute. Note that chemical resistant eyewear will be required if the end use product is classified as category I or II for eye irritation potential.

Inhalation exposures and risks were presented based on the oral toxicity endpoint ( i. e., route specific inhalation study not available). The surrogate unit exposure values were taken from the proprietary Chemical Manufacturers Association ( CMA) antimicrobial exposure study ( USEPA, 1999b: DP Barcode D247642) or from the Pesticide Handler Exposure Database ( USEPA, 1998). The specific inhalation unit exposures and quantity of DDAC handled are provided in the Occupational and Residential Exposure chapter for DDAC.

The inhalation MOEs were calculated for the short and intermediate term durations for occupational handlers using the oral endpoint.

Risk Characterization The resulting inhalation exposures and MOEs for the representative occupational handler scenarios are presented in Table 8.1. The calculated MOEs were above the target MOE of 100 for all scenarios. Page 25 of 52 Table 8.1 Short , Intermediate and Long Term Inhalation Risks Associated with Occupational Handlers Exposure Scenario Method of Application Inhalation Unit Exposure ( mg/ lb a. i.) Application Rate Quantity Handled/ Treated per day Inhalation Absorbed Daily Dose ( mg/ kg/ day) a Inhalation MOEb, c ( Target MOE = 100)

Agricultural Premises and Equipment ( Use Site Category I)

Mop 2.38 0.0094 lb ai/ gal 2 gallons 0.0075 13,000 High pressure/ high volume spray 0.12 0.0094 lb ai/ gal 40 gallons 0.00075 13,000 Low pressure hand wand 0.681 0.0094 lb ai/ gal 40 gallons 0.0043 2,300 Trigger pump sprayer 1.3 0.0094 lb ai/ gal 0.26 gallons 0.000052 190,000 Application to hard surfaces, equipment, and vehicles Wipe 67.3 0.0094 lb ai/ gal 0.26 gallons 0.0027 3,600 Fogging ( mix/ load only) Liquid pour 1.89 1.88E 05 lb/ ft3 150,000 ft3 0.089 110 Food Handling/ Storage Establishments Premises And Equipment ( Use Site Category II)

Low pressure hand wand 0.681 0.0200 lb ai/ gal 2 gallons 0.00045 22,000 Mop 2.38 0.0200 lb ai/ gal 2 gallons 0.0016 6,300 Wipe 67.3 0.0200 lb ai/ gal 0.26 gallons 0.0058 1,700 Trigger pump sprayer 1.3 0.0200 lb ai/ gal 0.26 gallons 0.00011 89,000 Application to indoor hard surfaces Immersion, Flooding, Circulation 1.89 0.00196 lb ai/ gal 2 gallons 0.00012 81,000 Commercial, Institutional and Industrial Premises and Equipment ( Use Site Category III )

Low pressure hand wand 0.681 0.0200 lb ai/ gal 2 gallons 0.00045 22,000 Mop 2.38 0.0200 lb ai/ gal 2 gallons 0.0016 6,300 Wipe 67.3 0.0200 lb ai/ gal 0.26 gallons 0.0058 1,700 Trigger pump sprayer 1.3 0.0200 lb ai/ gal 0.26 gallons 0.00011 89,000 Application to indoor hard surfaces Liquid pour 1.89 0.0043 lb ai/ gal 2 gallons 0.00027 37,000 Application to carpets Liquid pour 0.00346 0.102 lb ai/ gal 32 gallons 0.00019 53,000 Medical Premises and Equipment ( Use Site Category V)

Application to hard surfaces Mop 2.38 0.0200 lb ai/ gal 45 gallons 0.036 280 Industrial Processes and Water Systems ( Use Site Category VIII)

Liquid pour 0.45 4.17 lb ai/ gal product 2.5 gallons 0.078 130 Initial Dose ( ST): 1.50E 03lb ai/ gal water 20,000 gallons 0.0022 ST = 4,600 Small process water systems: Recirculating cooling tower Metering pump 0.00432 Maintenance Dose ( IT): 1.50E 04lb ai/ gal water 20,000 gallons 0.00022 IT = 46,000 5.6 gallons 0.00048 ST = 21,000 Oil field operations  drilling mud and packing fluids Liquid pour 0.00346 1.50 lb ai/ gal product 2.8 gallons 0.00024 IT = 41,000 Swimming Pools ( Use Site Category X) d Application to swimming pools Liquid pour 0.00346 Heavy algae Dose ( ST):

0.000017 lb ai/ gal 200,000 gallons 0.0002 ST= 15,000 Page 26 of 52 Table 8.1 Short , Intermediate and Long Term Inhalation Risks Associated with Occupational Handlers Exposure Scenario Method of Application Inhalation Unit Exposure ( mg/ lb a. i.) Application Rate Quantity Handled/ Treated per day Inhalation Absorbed Daily Dose ( mg/ kg/ day) a Inhalation MOEb, c ( Target MOE = 100)

Maintenance Dose ( IT/ LT):

0.00000417 lb ai/ gal 200,000 gallons 0.000048 IT= 210,000 ST = short term, IT = intermediate term, LT = long term, N/ A= No data available a Absorbed Daily dose ( mg/ kg/ day) = [ unit exposure ( mg/ lb a. i.) x absorption factor ( 1.0 for inhalation) x application rate x quantity treated / Body weight ( 60 kg for inhalation). b MOE = NOAEL ( mg/ kg/ day) / Absorbed Daily Dose [ Where NOAEL = 10 mg/ kg/ day for all inhalation exposure durations]. Target MOE = 100. c The MOEs refer to short term and intermediate term duration unless indicated otherwise. d. The swimming pool scenario also represents the decorative pond/ fountain scenario in the aquatic area use site category because the application rates are very similar.

8.2 Occupational Post application Exposures Except for the post application scenarios assessed for fogging wood preservatives ( Section 8.3), occupational post application dermal and inhalation exposures are assumed to be negligible.

Fogging ( Food Processing Plant and Hatchery) Post application inhalation exposures only were assessed for entry into a building ( hatchery and food processing plant) after a fogging application, because dermal post application is presumed to be negligible. The inhalation exposure assessment was conducted using the Multi Chamber Concentration and Exposure Model ( MCCEM v1.2). MCCEM estimates average and peak indoor air concentrations of chemicals released from products or materials in houses, apartments, townhouses, or other residences. Although the data libraries contained in MCCEM are limited to residential settings, the model can be used to assess other indoor environments. MCCEM has the capability to estimate inhalation exposures to chemicals, calculated as single day doses, chronic average daily doses, or lifetime average daily doses. ( All dose estimates are potential doses; they do not account for actual absorption into the body.)

The product, EPA Reg # 10324 80 ( 3.3% ai) with a maximum application rate of 0.0065 lb ai/ gal, was assessed for fogging use in a food processing plant. The label states to fog one quart of the diluted product per 1,000 cubic feet. All labels which can be used for fogging in food processing areas indicate that all personnel must vacate the room during fogging and for a minimum of 2 hours after fogging. Therefore, exposure was calculated for a person entering the food processing plant 2 hours after all the applied fogger has been deployed.

The MOE for fogging in the food processing plant ( 2 hr re entry interval) was below the target MOE of 100. For fogging in hatcheries, the 8 hr MOE is 120 immediately after fogging and 6,600 after a 2 hour REI. The risks of concern for the food processing plant are attributed to the low air changes per hour assumed ( i. e., 0.18 ACH as a default parameter in MCCEM to represent low air flow) in the assessment. This assessment can be refined with additional information on air flows in food processing plants. For the poultry barn, ventilation Page 27 of 52 rate was obtained from Jacobson ( 2005). The assessment for food processing plants could be refined if a more accurate ventilation rate could be obtained. Additional suggested label language to assure proper ventilation includes:

 ten air exchanges, or  2 hours of mechanical ventilation ( i. e., fans), or  4 hours of passive ventilation ( i. e., windows, vents), or  11 hours of no ventilation followed by 1 hour of mechanical ventilation, or  11 hours of no ventilation followed by 2 hours of passive ventilation, or  24 hours of no ventilation 8.3 Wood Preservation DDAC is used in products that are intended to preserve wood through both nonpressure treatment methods and pressure treatment methods. Section 8.3.1 presents the exposure analysis for the handler and post application scenarios for non pressure treatment scenarios and Section 8.3.2 presents the exposure analysis for the handler and post application scenarios for pressure treatment scenarios.

Dermal irritation exposures from post application activities in the wood preservation treatment facility will be mitigated using default personal protective equipment requirements based on the toxicity of the end use product. Therefore, only inhalation exposures and risks are presented.

8.3.1 Non Pressure Treatment Scenarios ( Handler and Post application)

The proprietary study, " Measurement and Assessment of Dermal and Inhalation Exposures to Didecyl Dimethyl Ammonium Chloride ( DDAC) Used in the Protection of Cut Lumber ( Phase III)" ( Bestari et al., 1999, MRID 455243 04) identified various worker functions/ positions for individuals that handle DDAC containing wood preservatives for nonpressure treatment application methods and for individuals that could then come into contact with the preserved wood. The worker functions/ positions identified in the DDAC study are presented below.

Handler:   Blender/ spray operators are workers that add the wood preservative into a blender/ sprayer system for composite wood via closed liquid pumping.   Diptank Operators can be in reference to wood being lowered into the treating solution through an automated process ( i. e., elevator diptank, forklift diptank). This scenario can also occur in a smaller scale treatment facility in which the worker can manually dip the wood into the treatment solution.   Chemical operators for a spray box system consist of chemical operators, chemical assistants, chemical supervisors, and chemical captains. These individuals maintain a chemical supply balance along with flushing and cleaning spray nozzles. Page 28 of 52 Post application:   Graders, positioned right after the spray box, grade dry lumber by hand ( i. e. detect faults). In the DDAC study, graders graded wet lumber; therefore, the exposures to graders using DDAC are worst case scenarios.   Millwrights repair all conveyer chains and general up keep of the mill.   Clean up crews perform general cleaning duties at the mill.   Trim saw operators operate the hula trim saw and consist of operators and strappers. In the DDAC study, hula trim saw operators handled dry lumber.   Construction workers install treated plywood, oriented strand board, medium density fiberboard, and others.

The blender/ spray operator position was assessed using CMA unit exposure data and the remaining handler and post application positions were assessed using data from the DDAC study ( Bestari et al., 1999).

Blender/ Spray Operators Table 8.2 provides the inhalation doses and MOEs for the workers adding the preservative to the wood slurry. The inhalation MOE is above the target MOE of 100 for short, intermediate, and long term inhalation exposures ( MOE = 280).

Table 8.2. Short, Intermediate, and Long Term Inhalation Exposures and MOEs for Blender/ Spray Operator Exposure Scenario Inhalation Unit Exposurea ( mg/ lb ai) Application Rate (% ai in solution/

day) Wood Slurry Treatedb ( lb/ day) Daily Dosec ( mg/ kg/ day) ST/ IT/ LT MOEd ( Target MOE = 100) Occupational Handler Blender/ spray operator 0.000403 3 178,000 0.036 280 ST = Short term duration; IT = Intermediate term duration; and LT = long term. a. Inhalation unit exposure: Baseline. b. Wood slurry treated = ( 8 batches/ day x 7,000 gallons/ batch x 0.003785 m3/ gallon x 380 kg/ m3 x 2.2 lb/ kg) c. Daily Dose = unit exposure ( mg/ lb ai) x App Rate (% ai/ day) x Quantity treated ( lb/ day) x absorption factor ( 100% for inhalation) / BW ( 60 kg) d. MOE = NOAEL ( mg/ kg/ day)/ Daily dose [ Where ST/ IT/ LT NOAEL = 10 mg/ kg/ day for inhalation. Target MOE = 100.

Chemical Operators, Graders, Millwrights, Clean up Crews, and Trim Saw Operators Table 8.3 provides the short, intermediate, and long term inhalation doses and MOEs for chemical operators, graders, millwrights, clean up crews, and trim saw operators. The inhalation MOEs are above the target MOE of 100 for all worker functions. Any dermal irritation exposures from post application activities will be mitigated using default personal protective equipment requirements based on the toxicity of the end use product.

Table 8.3. Short, Intermediate, and Long Term Inhalation Exposures and MOEs for Wood Preservative Chemical Operators, Graders, Trim Saw Operators, and Clean Up Crews ( Handler and Post application Activities)

Exposure Scenarioa ( number of volunteers) Inhalation UEb ( mg/ day) Conversion Ratioc Daily Dosed ( mg/ kg/ day) MOEe ( Target MOE = 100) Page 29 of 52 Table 8.3. Short, Intermediate, and Long Term Inhalation Exposures and MOEs for Wood Preservative Chemical Operators, Graders, Trim Saw Operators, and Clean Up Crews ( Handler and Post application Activities)

Exposure Scenarioa ( number of volunteers) Inhalation UEb ( mg/ day) Conversion Ratioc Daily Dosed ( mg/ kg/ day) MOEe ( Target MOE = 100)

Occupational Handlers Chemical Operator ( n= 11) 0.0281 NA 0.000468 21,000 Occupational Post Application Grader ( n= 13) 0.0295 NA 0.000491 20,000 Trim Saw ( n= 2) 0.061 NA 0.00101 9,900 Millwright ( n= 3) 0.057 NA 0.00095 11,000 Clean Up ( n= 6) 0.60 NA 0.0101 990 ST = Short term duration, IT = Intermediate term duration, LT = Long term duration a. The exposure scenario represents a worker wearing short sleeved shirts, cotton work trousers, and cotton glove dosimeter gloves under chemical resistant gloves. Volunteers were grouped according to tasks they conducted at the mill. b. Inhalation unit exposures are from Bestari et. al. ( 1999). Refer to Table E 1 in Appendix E for the calculation of the inhalation exposures. Inhalation exposure ( mg/ day) was calculated using the following equation: Air concentration ( µ g/ m3) x Inhalation rate ( 1.0 m3/ hr) x Sample duration ( 8 hr/ day) x Unit conversion ( 1 mg/ 1000 µ g). The inhalation rate is from USEPA, 1997. c. A conversion ratio is not needed because the maximum % active ingredient in the product is the same as the % active ingredient in the DDAC study. d. Daily dose ( mg/ kg/ day) = exposure ( mg/ day) x absorption factor ( 100% for inhalation)/ body weight ( 60 kg). e. MOE = NOAEL ( mg/ kg/ day)/ Daily dose [ Where inhalation NOAEL = 10 mg/ kg/ day]. Target MOE = 100.

Diptank Operators Exposures to diptank operators were also assessed using the data from the DDAC study ( Bestari et al., 1999). The diptank scenario assessment was conducted differently than for the other job functions because the concentration of DDAC in the diptank solution was provided. The exposure data for diptank operators were converted into A unit exposures @

in terms of mg a. i. for each 1% of concentration of the product. Table 8.4 provides the short, intermediate and long term inhalation dose and MOEs for diptank operators. The inhalation MOE is above the target MOE of 100 and, therefore, is not of concern.

Table 8.4. Short, Intermediate, and Long Term Inhalation Exposures and MOEs for Diptank Operator ( Handler Activity)

Exposure Scenarioa ( number of replicates) Inhalation Unit Exposureb ( mg DDAC/ 1% solution) App Rate (% a. i. in solution/ day) Daily Dosec ( mg/ kg/ day) MOEd Occupational Handler Dipping, with gloves ( n= 7) 0.046 3 0.0023 4,300 a The exposure scenario represents a worker not wearing a respirator. b Inhalation unit exposures are from DDAC study ( MRID 455243 04). Refer to Table E 2 in Appendix E for inhalation unit exposure calculations. Inhalation exposure ( mg) was calculated using the following equation: Air concentration ( mg/ m3) x Inhalation rate ( 1.0 m3/ hr) x Sample Duration ( 8 hr). The inhalation rate is from USEPA, 1997. c Daily dose ( mg/ kg/ day) = unit exposure ( mg/ 1% ai solution) x percent active ingredient in solution ( 3% ai) x absorption factor ( 100% for inhalation) / body weight ( 60 kg). Page 30 of 52 d MOE = NOAEL ( mg/ kg/ day) / Daily dose [ Where inhalation NOAEL = 10 mg/ kg/ day. Target MOE = 100.

Construction workers Potential risks resulting from construction worker dermal contact with DDAC treated wood are assessed in the same manner as potential risks resulting from children's dermal contact with DDAC treated play sets and decks. The risks were calculated using average worker residue data for hands available in the DDAC exposure study. Hand residue data from the end stacker, stickman, and tallyman workers were used because of the possibility of the contact with dry treated wood. The maximum and average values of these data ( 3.0 and1.4 : g/ cm2, respectively) were assumed to be the dermal skin irritation exposure. The dermal MOE are less than or equal to1 for maximum and average hand residues. A wood wipe study is needed to refine the risk estimates.

8.3.2 Pressure Treatment Scenarios ( Handler and Post Application)

DDAC may be used to treat wood and wood products using pressurized application methods such as double vacuum. According to the product labels, the maximum retention rate is 0.6 lb/ ft3. An application rate was not provided on the product labels; therefore, an application rate of 3% ai solution was used in this assessment, based on the master label. DDAC specific exposure data are not available for assessment of pressure treatment exposure. Therefore, the assessment relies on surrogate chromated copper arsenate ( CCA) data ( ACC, 2002b) and was based on the approach used in a previous exposure assessment ( USEPA, 2003b).

The estimated inhalation exposures and risks for DDAC are presented in Table 8.5. The calculated inhalation MOEs are above the target MOE of 100 for all scenarios.

Table 8.5. Short, Intermediate, and Long Term Inhalation Exposures and MOEs for Pressure Treatment Handler and Post application Scenarios Exposure Scenario Inhalation Unit Exposurea ( µ g As/ ppm) Application Rate (% ai solution) Absorbed Daily Dosesb ( mg/ kg/ day) Inhalation MOEsc ( Target MOE = 100) Occupational Handler Treatment Operator ( TO) 0.00257 3 0.0013 7,800 Treatment Assistant ( TA) 0.000802 3 0.00040 25,000 Occupational Post application All ( Tram setter, stacker operator, loader operator, supervisor, test borer, and tallyman) 0.00160 3 0.00080 13,000 a. Unit exposure values taken from CCA study and are shown in Table 6.11. b. Absorbed Daily Dose ( mg/ kg/ day) = Unit Exposure ( µ g As/ ppm) x [% DDAC in solution ( 3) x 10,000 ( parts per million conversion)] x ( 0.001 mg/ µ g) x absorption factor ( 100% for inhalation) / Body weight ( 60 kg). c. MOE = NOAEL ( mg/ kg/ day) / Daily dose [ Where inhalation NOAEL = 10 mg/ kg/ day for all durations. Target MOE = 100. Page 31 of 52 8.4 Data Limitations/ Uncertainties There are several data limitations and uncertainties associated with the occupational handler and post application exposure assessments. These include:

  Surrogate dermal and inhalation unit exposure values were taken from the proprietary Chemical Manufacturers Association ( CMA) antimicrobial exposure study ( USEPA, 1999b: DP Barcode D247642) or from the Pesticide Handler Exposure Database ( USEPA, 1998). Since the CMA data are of poor quality, the Agency requests that confirmatory data be submitted to support the occupational scenarios assessed in this document.   Unit exposures are not available for some of the specific scenarios that are prescribed for DDAC including open loading into oil well/ field environments o The CMA data used for oil well uses are based on open pouring of a material preservative. Although these data are only represented by 2 replicates each, the exposure values are similar to open loading of pesticides in PHED. Furthermore, there are no representative unit exposure data for chemical metering into secondary recovery oil operations. Since the volume of water being treated in secondary recovery operations is so large, the available CMA data can not be reliably extrapolated because they are based on activities that handle much lower volumes and possibly different techniques. Therefore, it was assumed that if the open pour handling activities for the other oil well operations resulted in MOEs that are not of concern, then the MOEs for the closed system chemical metering into secondary recovery operations would also be not of concern. The Agency requests that confirmatory data be conducted to show that this is accurate.   For the wood preservative pressure treatment scenarios, CCA exposure data were used for lack of DDAC specific exposure data. Limitations and uncertainties associated with the use of these data include: o The assumption was made that exposure patterns for workers at treatment facilities using CCA and DDAC would be similar to exposure patterns for workers at treatment facilities using DDAC, and therefore the exposures could be used as surrogate data for workers that treat wood with DDAC. o For environmental modeling, it was assumed that the leaching process from the DDAC treated wood would be similar to that of CCA and DDAC. However, due to the lack of real data for DDAC  treated wood, it is not possible to verify this assumption.   The quantities handled/ treated were estimated based on information from various sources, including HED's Standard Operating Procedures ( SOPs) for Residential Exposure Assessments ( USEPA, 2000 and 2001), and personal communication with experts. In particular, the use information for oil well uses and cooling water tower uses are based on personal communication with biocide manufacturers for these types of uses. The individuals contacted have experience in these operations and their estimates are believed to be the best available without undertaking a statistical survey of the uses. In certain cases, no standard values were available for some scenarios. Assumptions for these scenarios were based on AD estimates and could be further refined from input from registrants. Page 32 of 52   The percent active ingredient in solution for the pressure treatment of lumber needs to be refined by the registrant. The labels only provided a retention rate. For this assessment, the application rate on the master label was used, which is the same as the application rate for non pressure treatment of lumber.

9.0 INCIDENT REPORTS To review the evidence of health effects in humans resulting from exposure to QAC as stated in the PR Notice 88 1 ( February 26, 1988), the Agency has clustered Quats into four categories:

Group I. Alkyl or hydroxyalkyl ( straight chain) substituted quats; Group II Non halogenated benzyl substituted quats; Group III. Di and tri chlorobenzyl substituted quats; and Group IV. Quats with unusual substituents However for the available incident information, it is difficult to differentiate the specific members of the Quats involved in each incident. Therefore, all the Quats are discussed together.

The Agency consulted the following databases for poisoning incident data for DDAC:

( 1) OPP Incident Data System ( IDS)  The Incident Data System of The Office of Pesticide Programs ( OPP) of the Environmental Protection Agency ( EPA) contains reports of incidents from various sources, including registrants, other federal and state health and environmental agencies and individual consumers, submitted to OPP since 1992. Reports submitted to the Incident Data System represent anecdotal reports or allegations only, unless otherwise stated. Typically no conclusions can be drawn implicating the pesticide as a cause of any of the reported health effects. Nevertheless, sometimes with enough cases and/ or enough documentation risk mitigation measures may be suggested. ( 2) California Department of Pesticide Regulation ( 1982 2004)  California has collected uniform data on suspected pesticide poisonings since 1982. Physicians are required, by statute, to report to their local health officer all occurrences of illness suspected of being related to exposure to pesticides. The majority of the incidents involve workers. Information on exposure ( worker activity), type of illness ( systemic, eye, skin, eye/ skin and respiratory), likelihood of a causal relationship, and number of days off work and in the hospital are provided. ( 3) National Pesticide Telecommunications Network ( NPTN)  NPTN is a toll free information service supported by OPP. A ranking of the top 200 active ingredients for which telephone calls were received during calendar years 1984 1991, inclusive, has been prepared. The total number of calls was tabulated for the categories human incidents, animal incidents, calls for information, and others ( 4) Published Incident Reports  Some incident reports associated with Quats related human health hazard are published in the scientific literature.

There are many incident reported associated with exposure to end use products containing Quats. Dermal, ocular and inhalation are the primary routes of exposure. Most of the incidences are related to irritation. Allergic type reaction is also been reported in some Page 33 of 52 incidents. Although risk associated with eye exposure is not assessed in the risk assessment process, symptoms associated with eye are most commonly reported associated with Quats exposure. The most common symptoms reported for cases of ocular exposure were eye irritation/ burning, eye pain, conjunctivitis, swelling eye and swelling of eyelid.

The most common symptoms reported for cases of inhalation exposure were respiratory irritation/ burning, irritation to mouth/ throat/ nose, coughing/ choking, chest pain, disorientation, dizziness, shortness of breath.

The most common symptoms reported for cases of dermal exposure were skin irritation/ burning, rash, itching, and blistering. Allergic type reactions including hives and allergic contact dermatitis, have also been reported..

Although oral exposure is considered a minor route of exposure for Quats use, irritation to mouth/ throat/ nose, vomiting/ nausea/ abdominal pain, dizziness, and headache have been reported in the cases of ingestion.

10.0 ENVIRONMENTAL RISKS The results of the dietary avian studies indicate that DDAC is practically non toxic to both mallard duck and bobwhite quail. In the Acute oral studies, the chemical was found to be moderately toxic to bobwhite quail. The results from freshwater fish acute toxicity studies demonstrated that DDAC was moderately to highly toxic. DDAC is very highly toxic to freshwater aquatic invertebrates. DDAC is very highly toxic to mysid shrimp a marine/ estuarine invertebrate. DDAC is toxic to freshwater alga at microgram concentrations. Data Gaps: The following data requirements are outstanding for the currently registered uses of DDAC: 850.4225  Non target plant phytotoxicity testing ( seedling emergence test using rice). 850.1035  Acute Sheepshead minnow testing 850.1300  Acute eastern oyster embryo larvae testing 850.1300  Chronic Daphnis magna testing Monitoring/ Tier II modeling of once through cooling tower use to establish EEC's for risk assessment.

Tier I once through cooling tower modeling indicates that DDAC use will result in acute and chronic risk to all non endangered and endangered/ threatened aquatic organisms at all dosages modeled: 32 ppm and 63 ppm for continuous dosing and 1000 ppm and 1800 ppm for intermittent dosing. The high vs medium vs low water flow rate is based on size of the facility. Generally, higher flow ( e. g., > 1000 MGD) would use more chemical than smaller facilities, but the pattern does not hold true across the board, probably because model input values are based on different receiving water (" reach") data for individual facilities. This model uses 7Q10 rainfall conditions, which is essentially the worst case drought of a 10 year period. Variables such as stream flow rate and DDAC dissipation, degradation, and 1/ 2 life were not considered in this Tier I model but should be considered in higher tier modeling. Field monitoring is suggested in the absence of higher Tier modeling. Risk mitigation recommendations should be based on dosing method ( e. g. intermittent vs continuous) and application rate instead of facility size, Page 34 of 52 however, risk mitigation is not recommended at this time.

Wood Treatment Use: The maximum amount of leachate from treated wood per the Krahn and Strub, 1990 model totaled 18.97 ppb. The lowest predicted amount of leachate was 4.7 ppb and the highest amount was 113.8 ppb. Non endangered/ threatened aquatic species ( fish and invertebrates) are not expected to be adversely affected  acute or chronic toxicity  based on LOCs above. Endangered/ threatened fish ( freshwater warm water species) are not expected to be adversely affected by the wood treatment use. However, green alga non endangered/ threatened species, and freshwater fish coldwater species, freshwater and marine aquatic invertebrates, and green algae endangered/ threatened species are at risk from the wood treatment use.

Due to the extreme sensitivity of freshwater and marine aquatic invertebrates to DDAC, methods such as indoor or covered wood storage and/ or containment of runoff water via berms or plastic barriers in outdoor storage areas are suggested. DDAC is tightly adsorbed to clay and organic matter which greatly reduces potential for DDAC to leach downward through soil to groundwater, and will serve to reduce surface runoff as well.

Endangered Species Concerns: DDAC uses that have potential for direct release into the environment or runoff to surface waters include once through cooling tower and wood treatment uses respectively. These uses are considered to be representative of having worst case potential for impacting the environment. Therefore, these sites were modeled. The " best case" once through cooling tower scenario using 1/ 2 the maximum recommended label dosage intermittently applied in a low water flow resulted in LOC exceedances for all aquatic organisms used in the model, including freshwater fish, green alga, freshwater invertebrates, and marine invertebrates. The agency is not aware of any endangered or threatened green algae. Because DDAC is rapidly adsorbed to organic materials and clay, impacts to aquatic organisms may be less than modeled. Aerobic aquatic metabolism study on DDAC ( MRID# 422538 03) provides a sediment half life of 60 years. There is a potential for sediment concentrations to reach toxic levels over time ( aerobic soil metabolism half life of 2.8 years, MRID# 422538 01). The once through cooling tower model does not account for degradation and therefore, further assessment is required prior to making an agency endangered species determination. Endangered/ threatened coldwater fish species, marine and freshwater invertebrates, and green algae species are expected to be adversely affected by the wood treatment use. Impacts from the wood treatment use are not expected to occur as long as precautions are taken to prevent leaching when wood is stored outdoors.

The Environmental Fate and Effects Division ( EFED) has evaluated the outdoor use of the quaternary ammonium compounds, didecyl ammonium chlorides ( DDAC), being considered for reregistration by the Antimicrobial Division ( AD) ( DP Barcode D325481). Although primarily used as antimicrobial agents, DDAC is labeled for use in puddles and decorative pools to control algae. This use is intended for waterbodies generally disconnected from the greater watershed and will not likely result in exposure to nontarget aquatic species. It is possible these uses will result in exposure to amphibians utilizing these waterbodies for some portion of their lifecycle ( e. g. reproduction) and to birds and mammals utilizing these waterbodies for drinking water. At the maximum label rate, 3 ppm initially followed by Page 35 of 52 weekly 1.5 ppm treatments, there are no LOC exceedances, assuming the toxicity of DDAC is similar to that of ADBAC. However, due to the persistence of DDAC, it is possible that concentrations of DDAC in some waterbodies treated over time could become harmful to animals utilizing these waterbodies. Page 36 of 52 11.0 REFERENCES American Chemistry Council ( ACC). 2002a. Assessment of Potential Inhalation and Dermal Exposure Associated With Pressure Treatment of Wood with Arsenical Wood Products. MRID 4550211 01.

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41886701 ( MRID) Neeper Bradley, T. ( 1991) Development Toxicity Evaluation of Didecyldimethylammoniumchloride Administered by Gavage to CD ( Sprague Dawley) Rats: Lab Project Number: 53 534. Unpublished Study prepared by Bushy Run Research Center. 282 p.

42746901 ( MRID) Neeper Bradley, T. ( 1993) Developmental Toxicity Dose Range Finding Study of Didecyldimethylammoniumchloride Administered by Gavage to CD ( Sprague Dawley) Rats: Lab Project Number: 53 533. Unpublished study prepared by Bushy Run Research Center. 106 p.

41018701 ( MRID) Tyl, R. ( 1989) Developmental Toxicity Study of Didecyldimethylammonium chloride Administered by Gavage to New Zealand White Rabbits: Project ID: 51 590. Unpublished study prepared by Bushy Run Research Center. 164 p.

41804501 ( MRID) Neeper Bradley, T. ( 1991) Two Generation Reproduction Study in Sprague Dawley ( CD) Rats with Didecyldimethylammonium chloride Administered in the Diet: Lab Project Number: 52 648. Unpublished study prepared by Bushy Run Research Ctr. 758 p.

41970401 ( MRID) Schulze, G. ( 1991) Chronic Oral Toxicity Study of Didecyldimethylammonium chloride in Dogs: Final Report: Lab Project Number: 2545 102. Unpublished study prepared by Halzeton Washington, Inc. 335 p.

41965101 ( MRID) Gill, M.; Chun, J.; Wagner, C. ( 1991) Chronic Dietary Toxicity/ Oncogenicity Study with Didecyldimethyl ammoniumchloride in Rats: Lab Project Number: 53/ 566. Unpublished study prepared by Bushy Run Research Center. 1649 p.

41802301 ( MRID) Gill, M.; Hermansky, S.; Wagner, C. ( 1991) Chronic Dietary Oncogenicity Study with Didecyldimethylammonium chloride in Mice: Lab Project Number: 53 528. Unpublished study prepared by Bushy Run Research Center. 1006 p.

40282201 ( MRID) Friederich, U.; Wurgler, F. ( 1982) Salmonella/ Mammalian Microsome Assay with Bardac 22. Unpublished study prepared by Institute of Toxicology, Swiss Federal Page 40 of 52 Institute of Technology, and University of Zurich. 18 p.

44005801 ( MRID) Schoenig, G. ( 1996) Response to EPA Data Evaluation Report for Study Entitled: " Salmonella/ Mammalian Microsome Assay with Bardac 22." Unpublished study prepared by Institute of Toxicology, Swiss Federal Institute of Technology and University of Zurich. 14 p.

93014007 ( MRID) Schoenig, G. ( 1990) Lonza Inc Phase 3 Summary of MRID 40895201. Mutagenicity Test on Didecyldimethylammoniumchloride in the Rat Hepatocyte Unscheduled DNA Synthesis Assay: Project No. 10141 0 447. Prepared by Hazleton Laboratories America, Inc. 14 p.

40895202 ( MRID) Young, R. ( 1988) Mutagenicity Test on Didecyldimethyl Ammonium Chloride ( DDAC) in the CHO/ HGPRT Forward Mutation Assay: HLA Study No. 10141 0 435. Unpublished study prepared by Hazleton Laboratories America, Inc. 68 p.

41252601 ( MRID) Holmstrom, M.; Leftwich, D.; Leddy, I. ( 1986) PO151: Chromosomal Aberrations Assay with Chinese Hamster Ovary Cells in vitro: Proj. No. 735717. Unpublished study prepared by Lonza Inc. 36 p.

93014008 ( MRID) Schoenig, G. ( 1990) Lonza Inc Phase 3 Summary of 40895202. Mutagenicity Test on Didecyldimethylammoniumchloride in the CHO/ HGPRT Forward Mutation Assay: Project No. 10141 0 435. Prepared by Hazleton Laboratories America, Inc. 17 p.

40895201 ( MRID) Cifone, M. ( 1988) Mutagenicity Test on Didecyldimethylammonium Chloride in the Rat Primary Hepatocyte Unscheduled DNA Synthesis Assay: HLA Study No. 10141 0 447. Unpublished study prepared by Hazleton Laboratories America, Inc. 60 p.

41617101 ( MRID) Selim, S. ( 1989) Absorption, Distribution, Metabolism and Excretion Studies of Didecyldimethylammoniumchloride ( DDAC): Lab Project Number: P01421. Unpublished study prepared by Biological Test Center. 197 p.

41385101 ( MRID) Lin, P.; Selim, S. ( 1989) Addendum to Report Entitled Absorption, Distribution, Metabolism and Excretion Studies of Didecyldimethylammonium chloride ( DDAC) in the Rat: Lab Project Number: P01421. Unpublished study prepared by Biological Test Center. 269 p.

USEPA ( 2000): Didecyl Dimethyl Ammonium Chloride ( DDAC)   Report of the Hazard Identification Assessment Review Committee. HED document No. 014099.

USEPA ( 2000): Didecyl Dimethyl Ammonium Chloride: Toxicology Review. DP Barcode D260952.

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Preller, L.; Doekers, G.; Heederik, D.; Vermulen, R.; Vogelzang, P. F. J, and Boleij, J. S. M. 1996. Disinfinfectant use as a risk factor for atopic sensitization and symptoms consistent with asthma: an epidemiological study. European Respiratory Journal: 9 ( 7) 1407 1413.

Shmunes, E. and Levy, E. J. 1972. Quaternary ammonium compound contact dermatitis from deodorant. Arch Dermatol. 105( 1) 91 93.