Final Contaminant Candidate List 3 

Chemicals: Screening to a PCCL 
Office of Water (4607M) 

EPA 815-R-09-007 

August 2009 

www.epa.gov/safewater 
 

EPA-OGWDW Final CCL 3 Chemicals: EPA 815-R-09-007 

Screening to a PCCL August 2009 

Table of Contents 

1.0 INTRODUCTION ........................................................................................................................ 1
 

2.0 HEALTH EFFECTS DATA ELEMENTS....................................................................................... 3
 

2.1 Dose-Response Data Elements ........................................................................................... 4 

2.2 Categorical Data Elements .................................................................................................. 5 

2.3 Calibration of the Data for Partitioning into Toxicity Categories....................................... 6 

2.3.1 Dose-Response Data..................................................................................................... 6 

2.3.2 Categorical Data ........................................................................................................... 9 

2.4 Combining the Data Elements for Screening .................................................................... 12 

3.0 OCCURRENCE DATA ELEMENTS ........................................................................................... 13
 

3.1 Finished Water Data .......................................................................................................... 13 

3.2 Ambient Water Data ......................................................................................................... 15 

3.3 Environmental Release Data ............................................................................................. 15 

3.4 Production Data................................................................................................................. 16 

3.5 Disinfection Byproducts (DBPs) and Drinking Water Treatment Chemicals .................. 16 

3.6 Combining the Data Elements for Screening .................................................................... 16 

4.0 CRITERIA FOR SELECTING A PCCL...................................................................................... 17
 

4.1 Finished and Ambient Water Concentration Data ............................................................ 17 

4.2 Environmental Release Data ............................................................................................. 18 

4.3 Production Data................................................................................................................. 19 

4.4 DBPS and Drinking Water Additives ............................................................................... 20 

5.0 EFFICACY OF THE FRAMEWORK AS A SCREENING TOOL..................................................... 20
 

6.0 REFERENCES .......................................................................................................................... 21
 

7.0 APPENDICES ....................................................................................................................... A1-1
 

Appendix 1. Criteria for Selecting the PCCL ...................................................................... A1-1 

Appendix 2. Chemicals Passing Screening to the PCCL ..................................................... A2-1 

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Table of Exhibits 

Exhibit 1: Partition for Screening the Universe ............................................................................. 3 

Exhibit 2: Potency Distributions for the Health Effects Test Set and Universe Chemicals .......... 7 

Exhibit 3: Hodge Sterner Scale for Categorizing Chemicals Based on LD50 Values 

(Health Canada, 2005) ........................................................................................................ 8 

Exhibit 4: Potency Measures for Universe Data Element Partitioned Based on Toxicity 

(mg/kg/day or mg/kg) ......................................................................................................... 9 

Exhibit 5: Cancer Grouping and Description under the U.S. EPA 1986 Guidelines ..................... 9 

Exhibit 6: IARC Cancer Groupings (ITER, 2006) ...................................................................... 10 

Exhibit 7: Partitioning of Cancer Data Based on TD50 Values and Weight of Evidence ............ 11 

Exhibit 8: Examples of Potency Data Elements for the Selected Chemical Drawn from 

the Universe ...................................................................................................................... 12 

Exhibit 9: Number of Chemicals with Median Concentrations Distributed through the 

Screening Framework by Health Effects Category .......................................................... 14 

Exhibit 10: Criteria for Screening Health Effects and Water Categories .................................... 18 

Exhibit 11: Criteria for Screening Health Effects and Environmental Release Categories ......... 19 

Exhibit 12: Criteria for Screening Health Effects and Production Categories ............................ 19 

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List of Acronyms and Abbreviations 

< Less than 

≤ Less than or equal to 

> Greater than 

≥ Greater than or equal to 

μg/L Micrograms per liter 

CASRN Chemical Abstract Services Registry Number 

CCL Contaminant Candidate List 

CCL 1 EPA’s first contaminant candidate list 

CCL 3 EPA’s third Contaminant Candidate List 

CE Clear evidence of carcinogenicity 

CUS/IUR Chemical Update System/Inventory Update Rule 

DBPs Disinfection By-Products 

DBP-CAN Disinfection By-Product with Carcinogenicity Estimates 

DSS-Tox Distributed Structure-Searchable Toxicity 

DWEL Drinking water equivalent level 

E Equivocal 

EE Equivocal evidence of carcinogenicity 

EPA United States Environmental Protection Agency 

FDA United States Food and Drug Administration 

FW/AW Finished Water/Ambient Water 

H High probability of causing cancer 

HM High moderate probability of causing cancer 

IRIS Integrated Risk Information System (EPA) 

kg Kilogram 

L Liter 

L Low probability of causing cancer 

LD50 Lethal dose 50; an estimate of a single dose that is expected to cause the 

death of 50 percent of the exposed animals; it is derived from experimental 

data. 

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lbs Pounds 

LM Low moderate probability of causing cancer 

LOAEL Lowest observed adverse effect level 

M Moderate probability of causing cancer 

Mar Marginal probability of causing cancer 

MCLG Maximum contaminant level goal 

MRDD Maximum recommended daily dose 

mg/kg Milligrams per kilogram body weight 

mg/kg/day Milligrams per kilogram body weight per day 

N Negative 

NAWQA National Water Quality Assessment Program (USGS) 

NCFAP National Center for Food and Agricultural Policy 

NCI National Cancer Institute 

NDWAC National Drinking Water Advisory Council 

NE No evidence of carcinogenicity 

NOAEL No observed adverse effect level 

NPDWR National Primary Drinking Water Regulations 

NREC National Reconnaissance of Emerging Contaminants 

NTP National Toxicology Program 

NTPMSR National Toxicology Program multi-species results 

P Positive 

PCCL Preliminary CCL 

PPMP Pesticide Pilot Monitoring Program 

RfD Reference dose 

QSAR Quantitative Structure Activity Relationship 

RfD-eq Reference Dose -equivalent 

SE Some evidence of carcinogenicity 

TD50 Tumorigenic dose 50; The dose-rate which if administered chronically for 

the standard life-span of the species will have a 50% probability of causing 

tumors at some point during that period. 

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EPA 815-R-09-007 

August 2009 

TRI Toxics Release Inventory 

TS Test Set of chemicals 

U Universe 

USGS United States Geological Survey 

yr Year 

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1.0 Introduction 

Every five years the United States Environmental Protection Agency (EPA) is required to 

publish a list of contaminants (1) that are currently unregulated, (2) that are known or anticipated 

to occur in public water systems, and (3) which may require regulations under the Safe Drinking 

Water Act (SDWA). This list is known as the Contaminant Candidate List or CCL. SDWA 

section 1412(b)(1) requires that in the development of the CCL, EPA consider specific data 

sources and include the scientific community. EPA must evaluate substances identified in section 

101(14) of the Comprehensive Environmental Response, Compensation, and Liability Act 

(CERCLA) of 1980 and substances registered as pesticides under the Federal Insecticide, 

Fungicide, and Rodenticide Act (FIFRA). SDWA also requires the Agency to consider the 

National Contaminant Occurrence Database established under section 1445(g) of SDWA. 

SDWA directs the Agency to consult with the scientific community, including the Science 

Advisory Board (SAB). In addition, it directs the Agency to consider the health effects and 

occurrence information for unregulated contaminants to identify those contaminants that present 

the greatest public health concern related to exposure from drinking water. 

 

EPA interprets the criterion that contaminants are known or anticipated to occur in public water 

systems broadly. In evaluating this criterion, EPA considers not only public water system 

monitoring data, but also data on concentrations in ambient surface and ground waters, releases 

to the environment (e.g., Toxics Release Inventory), and production. While such data may not 

establish conclusively that contaminants are known to occur in public water systems, EPA 

believes these data are sufficient to anticipate that contaminants may occur in public water 

systems and support their inclusion on the CCL. The Agency considered adverse health effects 

that may pose a greater risk to life stages and other sensitive groups which represent a 

meaningful portion of the population. Adverse health effects associated with infants, children, 

pregnant women, the elderly, and individuals with a history of serious illness were evaluated. In 

selecting contaminants for the CCL 3, each of the above requirements was met. 

SDWA section 1412(b)(1) also requires EPA to determine whether to regulate at least five 

contaminants from the CCL every five years. SDWA specifies that EPA shall regulate a 

contaminant if the Administrator determines that: 

 The contaminant may have an adverse effect on the health of persons; 

 The contaminant is known to occur, or there is a substantial likelihood that the 

contaminant will occur in public water systems with a frequency and at levels of public 

health concern; and 

 In the sole judgment of the Administrator, regulation of such contaminant presents a 

meaningful opportunity for health risk reduction for persons served by public water 

systems. 

Once contaminants have been placed on the CCL, EPA identifies if there are any additional data 

needs or if there are sufficient information to make a regulatory determination. EPA interprets 

these criteria for regulatory determination as more rigorous than what is used to place 

contaminants on the CCL. 

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EPA developed a multi-step process, based on available data, to characterize occurrence and 

adverse health risks a contaminant may pose to consumers of public water systems for inclusion 

on the Contaminant Candidate Lists (CCL). The steps involve: 

1) Building a broad CCL Universe of potential drinking water contaminants for 

consideration (see “Final Contaminant Candidate List 3 Chemicals: Identifying the 

Universe” (USEPA, 2009a)); 

2) Using straightforward screening criteria related to a contaminant’s potential to occur in 

drinking water and potential for public health concern to narrow the Universe to a 

Preliminary CCL (PCCL), and; 

3) Using a structured classification approach (e.g., a classification model) as a tool, along 

with expert judgment, to develop a proposed CCL from the PCCL (see “Final 

Contaminant Candidate List 3 Chemicals: Classification of the PCCL to the CCL” 

(USEPA, 2009b)). 

4) Providing opportunities for public comment and contaminant nomination (see “Summary 

of Nominations for the Third Contaminant Candidate List” (USEPA, 2009c)). 

This report focuses on the second step, in which EPA uses an approach to screen chemicals to a 

PCCL using the data available from a set of data sources that EPA evaluated for health effects 

and occurrence information to compile the CCL 3 Universe. 

These data sources have yielded over 6,000 chemicals which populate the CCL 3 Chemical 

Universe. Along with the names and identifying characteristics of these chemicals the Universe 

is the repository for the health-related and occurrence-related information. This information was 

used to screen individual contaminants to determine if they should advance from the Universe to 

the PCCL. In the case of health effects, the Universe includes both quantitative and qualitative 

information on the hazard and/or dose-response properties of the contaminants. For occurrence, 

the Universe includes both quantitative and qualitative information on occurrence in water, 

releases to the environment, and amount produced. The process for the selection of data sources 

and Universe chemicals is detailed in the document entitled, “Contaminant Candidate List 3 

Chemicals: Identifying the Universe” (USEPA, 2009a). 

EPA based the screening approach, in part, on the National Drinking Water Advisory Council 

(NDWAC) recommendation that screening the Universe of chemicals for selection of the PCCL 

should be based on widely available data elements that represent important health effects and 

occurrence properties (NDWAC, 2004). NDWAC also recommended that the screening be 

versatile, yet as simple as possible, and facilitate the identification of those contaminants most in 

need of further consideration through the PCCL to CCL process. EPA considered this an 

important goal when establishing the screening criteria. 

The basic framework developed by EPA for use in screening is shown in Exhibit 1. Applying 

this framework to the CCL 3 Universe groups contaminants categorized by their toxicity along 

the vertical axis and by their occurrence on the horizontal axis. It arrays the data in a way that 

will allow for a separation of chemicals into those that move to the PCCL based on their toxicity 

and occurrence properties (e.g., upper right in Exhibit 1) and those that are not further evaluated 

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Exhibit 1: Partition for Screening the Universe 

Health Effects 

Occurrence 

Low to High Occurrence 

Increasing 

Toxicity 

Do not pass to PCCL Pass to the PCCL 

 

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and remain in the CCL chemical universe (e.g., lower left in Exhibit 1). The type of available 

data determines which chemicals move to the PCCL and those that remain in the universe. 

To adequately represent the broad spectrum of health effects data elements at the screening level, 

the toxicity categories must accommodate both dose-response and descriptive data. The 

occurrence screening categories must also accommodate a variety of occurrence data elements 

such as water concentration, environmental release, or production data. 

The challenge in screening is to group the chemicals into categories for health effects and 

occurrence using the variety of data elements available in the Universe in a generally equivalent 

manner. Section 2.0 describes the approach that was used for grouping the health effects data 

elements into the separate toxicity-based categories. Section 3.0 describes the approach that is 

used to group the occurrence data elements. The application of the screening framework as a 

tool, and the results from screening are discussed in Section 4.0. Appendix 1 summarizes the 

screening criteria for each type of data considered. Appendix 2 shows the contaminants and the 

data EPA used that moved them to the PCCL for additional consideration in the CCL 3 process. 

2.0 Health Effects Data Elements 

The toxicity information and health effects data extracted from the data sources are quite varied 

(USEPA, 2009a and b). The health data elements that provide toxicity information to populate 

Exhibit 1 fall into two major categories: 

 Data elements that provide dose-response information (potency) 

 Categorical data elements on hazard (mostly related to carcinogenic potential). 

Some chemicals come from data sources that provide dose-response data in the form of Lowest 

Observable Adverse Effects Level (LOAELs), Lethal Dose 50 (LD50), or Reference Doses and 

their equivalents (RfDs and RfD-eq). Some data sources only include descriptive data such as the 

positive, negative, or equivocal results from National Toxicology Program (NTP) studies or 

International Agency for Research on Cancer (IARC) carcinogen classifications. Still other 

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chemicals are in the Universe by virtue of their being on a list, such as the State of California list 

of reproductive or developmental toxicants (“Proposition 65”) which does not have any 

accompanying toxicological data. For this reason, it is important that the screening process for 

deriving the PCCL be able to accommodate a variety of health effects data inputs. 

After examining the breadth of available health effects data, EPA established five categories for 

screening. The five categories are as follows: 

	 Toxicity Category 1 

	 Toxicity Category 2 

	 Toxicity Category 3 (the central tendency grouping) 

	 Toxicity Category 4 

	 Toxicity Category 5 

The toxicity of the grouping decreases as the number for the grouping increases, with Toxicity 

Category 1 being the most toxic grouping and Toxicity Category 5 the least toxic grouping. 

Within each Toxicity Category, the partitioning criteria vary depending on the data element used. 

The partitioning criteria that place a LOAEL in Toxicity Category 1 differ from the criteria used 

for LD50 values that place it in the same category. Both criteria are intended to identify 

contaminants of approximately equivalent toxicity. The following sections provide information 

on the data elements available in the Universe that reflect the dose-response properties and 

categorical or descriptive information for the chemicals in the Universe. 

2.1 Dose-Response Data Elements 

The NDWAC recommended that screening be based on data elements that demonstrate toxic 

effects (i.e., LOAELs, LD50s, Cancer Slope Factors, etc.) rather than on data elements that are 

based on no effects (i.e., No observed adverse effect level (NOAELs) or that include uncertainty 

factors in their derivation (i.e., RfD-eq). However, because of the limitations on the types of data 

available for many of the contaminants, it is not possible to be this restrictive. Of the chemicals 

in the universe, about 500 had LOAEL data and about 2,000 had LD50 data. The remainder were 

lacking the endpoints recommended by the NDWAC, so EPA used other data elements that 

provide quantitative information on dose-response that can be partitioned into the five toxicity 

groupings. Major endpoints that fall in this category, in addition to LOAELs and LD50s, are as 

follows: 

	 RfDs and RfD-equivalents: RfDs, Minimal Risk Levels from the Agency for Toxic 

Substance and Disease Registry, Tolerable Daily Intakes from the World Health 

Organization (WHO), Acceptable Daily Intakes from WHO and the Food and Drug 

Administration (FDA), Public Health Goals from California EPA, and Tolerable Upper 

Intake Levels from the Institute of Medicine. 

	 NOAELs - No Observed Adverse Effect Levels. 

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	 50

species will have a 50% probability of causing tumors throughout that period. Chemicals 

with TD50 data have positive cancer results in at least one study. 

	 Maximum Recommended Daily Dose (MRDD) - Recommendations for the maximum 

adult daily therapeutic doses for pharmaceuticals (FDA). 

Including the measures of toxic potency listed above in the health effects screening framework 

expands the number of chemicals from the Universe that can be screened on the basis of their 

dose-response for possible inclusion in the PCCL. The approach used to partition each of these 

toxicity measures for screening is described in Section 2.3. 

2.2 Categorical Data Elements 

There are three groups of categorical data elements and health effects information in the 

Universe. These groups categorize chemicals according to their carcinogenic potential, 

mutagenicity information, or classification as a developmental or reproductive toxicant. 

Categorical data sets in the Universe include the following: 

	 U.S. EPA Cancer Groupings 

	 IARC Cancer Groupings 

	 NTP weight-of-evidence findings from cancer bioassays 

	 National Cancer Institute (NCI) weight-of-evidence findings from cancer bioassays 

	 California EPA list of chemicals suspected of causing cancer 

	 EPA Water Disinfection By-Products with Carcinogenicity Estimates (DBP-CAN) 

groupings based on carcinogenic potential derived from Quantitative Structure Activity 

Relationship (QSAR) projections and expert judgment 

	 California list of chemicals suspected of being developmental or reproductive toxicants 

	 U.S. EPA groupings of disinfection by-products (DBPs) based on QSAR predictions of 

their ability to cause developmental or reproductive toxicity. 

Even with the expansion of the types of dose-response data suitable for screening described in 

Section 2.1, many chemicals in the Universe lack dose-response data elements making it 

important to use the categorical information at this screening stage. 

The categorical cancer information is amenable to the screening approach illustrated in Exhibit 1 

because, in most cases, it includes subcategories related to the strength of the cancer data and its 

applicability to humans. 

The second group of categorical data elements provides information on genotoxicity and 

mutagenicity. This group is considered categorical because results are classified as positive, 

negative, or equivocal. However, it is common to have multiple genotoxicity assays for any 

given chemical, and it is unusual for all assays of a given chemical to have the same result. 

TD s - The dose-rate which if administered chronically for the standard life-span of the 

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Accordingly, there is a need to integrate all of the genotoxicity results and determine a 

categorical weight-of-evidence if the data are to be useful for screening. However, the Universe 

contained few weight-of-evidence findings on genotoxicity, and, when such results are available, 

they are usually tied to cancer assessments with dose-response measures. Accordingly, the use of 

the categorical cancer information along with TD50 dose-response data reduces the importance of 

including genotoxicity as a screening criterion. The genotoxicity data remain available as a 

supplemental health effects element that can be applied in the evaluation of the PCCL and in 

making decisions for chemicals that fall close to the screening barrier that separates the 

chemicals that will move to the PCCL from those that will remain in the Universe. 

The third type of categorical information in the database comes from the State of California’s list 

of reproductive and developmental toxicants or other similar lists. These lists are groupings that 

are based on a single toxicological property, but not partitioned by the degree of hazard. In this 

respect the lists are different from the cancer information that includes subdivisions based on the 

hazard weight-of-evidence and supported by quantitative cancer slope factors and/or TD50 

values. For this reason, the California list of developmental and reproductive toxicants and the 

California list of carcinogens are not used for the screening framework but they are retained as 

supplemental information that may be useful in the evaluation of the initial PCCL screening 

results. 

2.3 Calibration of the Data for Partitioning into Toxicity Categories 

2.3.1 Dose-Response Data 

As mentioned in the previous section, the health effects information found in the Universe is 

diverse. Accordingly, the challenge in screening is to be able to partition each type of data 

element into the five toxicity-based categories in a reproducible and logical manner. The main 

data elements proposed for screening (RfD-eq, NOAEL, and LOAEL values) have been used by 

EPA in establishing Maximum Contaminant Level Goals (MCLGs) or Lifetime Health 

Advisories. Accordingly, it was possible to compile a set of test chemicals (TS) found in 

drinking water that had multiple data elements from the set of toxicity data (i.e., RfD-eq, 

NOAEL, LOAEL, LD50) and examine the range and distribution of values associated with each 

dose-response data element. Distributions were also determined for the other measures of doseresponse found in the Universe (U) at the time the screening process was developed (i.e., 

LOAELs, LD50s, MRDDs, TD50s). Each measure of toxicity covered a range of close to ten 

orders of magnitude and had a roughly normal distribution when arrayed according to their log10 

value rounded to a single significant figure (Exhibit 2). Each data set is skewed toward higher 

potency chemicals due to the difficulty in identifying conventional toxicity data for many 

chemicals that are slightly or practically nontoxic. The RfDs and NOAELs in the Universe were 

not initially compiled. 

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Exhibit 2: Potency Distributions for the Health Effects Test Set 

and Universe Chemicals 

Log RfD-eq NOAEL LOAEL MRDD TD50 LD50 

TS TS TS U U U TS U 

<-7 1 

-7 

-6 1 

-5 8 3 

-4 59 1 3 4 3 

-3 105 5 2 4 15 8 

-2 121 21 13 15 53 17 0 1 

-1 63 45 28 52 183 53 0 1 

0 11 92 63 83 271 184 9 10 

1 4 106 121 120 453 266 11 26 

2 3 29 85 139 223 272 45 239 

3 13 28 73 12 139 75 1023 

4 1 8 25 40 672 

5 1 1 19 

6 

TS = Test Set, U= Universe 

The TS for RFDs includes chemicals on the IRIS as well as those with MCLGs 

and/or Health Advisory values 

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A reference point for the potency of drinking water was established by converting the 2 L/day, 

90 percentile drinking water intake (used by the Office of Water for risk analyses), into a 

NOAEL equivalent mg/kg/day dose for 70 Kg adults. This dose equivalent, for perspective, 

would occur in the Log 5 cell in the NOAEL health effects diagnostic set. Including this doseresponse value for drinking water allows all other contaminants to be viewed in perspective as 

they relate to the CCL screening framework (in Exhibit 2). 

EPA evaluated the distribution of the Test Set or the Universe dose-response parameters shown 

in Exhibit 2. EPA defined the modal grouping from the distribution for each type of toxicity 

parameter as Toxicity Category 3 for screening. The higher and lower screening toxicity 

categories were partitioned from the remainder of the distribution based on its shape and the 

numeric groupings of chemicals above and below the modal grouping. For most parameters other 

than the LD50 values, partitioning was based on powers of 10 and a desire to be more inclusive 

rather than exclusive during the screening process, especially during initial testing. 

There is a discrepancy between the modal LOAEL in the Universe and that from the Test Set. 

The data from the Universe have a modal value that is one log10 unit less toxic than that for the 

Test Set (Exhibit 2). A decision was made by EPA to base Toxicity Category 3 LOAEL 

grouping on the Test Set rather than the universe because the combination of the Office of Water 

Health Advisory chemicals and those on Integrated Risk Information System (IRIS) that made 

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up that set is more representative of chemicals that EPA had found to be of environmental and/or 

regulatory concern than the Universe compilation. 

The partitioning for the LD50 values was treated differently from the RfD-eq, NOAEL, and 

LOAEL values because there has long been an accepted categorization of LD50 values into six 

categories. The Hodge Sterner scale is shown in Exhibit 3 (Hodge Sterner, 1956). The six 

categories were reduced to the five screening categories by combining the two lowest toxicity 

categories from the Hodge Sterner Scale. 

Exhibit 3: Hodge Sterner Scale for Categorizing Chemicals 

Based on LD50 Values (Health Canada, 2005) 

Extremely Toxic <1 mg/kg 

Highly Toxic 1 - <50 mg/kg 

Moderately Toxic 50 - <500 mg/kg 

Slightly Toxic 500 - <5000 mg/kg 

Practically nontoxic 5000 - <15000 mg/kg 

Relatively harmless ≥15000 mg/kg 

The MRDD values were partitioned as if they were LOAELs because the maximum therapeutic 

doses are established by balancing their benefit with their risk. Accordingly, although MRDD 

doses are safe for human consumption, some adverse effects are always possible, especially in 

sensitive populations. This situation justifies considering them as LOAELs rather than NOAELs. 

The partitioning of the TD50 values was unique in that they apply to the probability for tumor 

development. They were, accordingly, combined with the categorical data elements that are 

discussed in Section 2.3.2. 

Exhibit 4 illustrates how the Universe dose-response data elements partition into their toxicity 

categories for screening. The partitioning considered both the distribution of the data for each of 

the health effects data elements and the number of contaminants that would fall in each of the 

toxicity categories. The testing of the partitioning for the third CCL (CCL 3) Universe at the time 

of protocol development suggested that the approach performed reasonably well. Its performance 

can be further evaluated and modified if needed for future CCLs. 

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Exhibit 4: Potency Measures for Universe Data Element Partitioned 

Based on Toxicity (mg/kg/day or mg/kg) 

RfD NOAEL LOAEL MRDD LD50 

Toxicity Category 1 <0.0001 <0.01 <0.01 <0.01 <1 

Toxicity Category 2 0.0001 - <0.001 0.01 - < 1 0.01 - <1 0.01 - < 1 1 - <50 

Toxicity Category 3 0.001 - <0.05 1 - <10 1 - <10 1 - <10 50 - <500 

Toxicity Category 4 0.05 - <0.1 10 - < 1000 10 - <1000 10 - < 1000 500 - <5000 

Toxicity Category 5 ≥0.1 ≥1000 ≥1000 ≥1000 ≥5000 

Exhibit 5: Cancer Grouping and Description under the 

U.S. EPA 1986 Guidelines 

Group Description 

A Human carcinogen 

B1 Probable human carcinogen 

B2 Limited evidence in animals and inadequate or no evidence in humans 

C Possible human carcinogen 

D Not classifiable as to human carcinogenicity 

E Evidence of noncarcinogenicity in humans 

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2.3.2 Categorical Data 

As discussed in Section 2.0, the categorical data selected for screening were primarily those that 

applied to cancer and provided a weight-of-evidence evaluation for the probability that the agent 

was carcinogenic to humans. The data from the EPA include either an alpha-numeric grouping or 

a weight-of-evidence statement on carcinogenic potential and often a cancer slope factor. The 

alpha-numeric groupings (Exhibit 5) apply to the chemicals evaluated for their carcinogenicity 

under the Guidelines for Carcinogen Risk Assessment (USEPA, 1986). 

In 1996 and 1999 the U.S. EPA issued draft updated guidelines for evaluating carcinogenicity. 

EPA finalized the revised guidelines in 2005 (USEPA, 2005). Chemicals evaluated under the 

2005 Guidelines and its drafts are grouped according to five weight-of-evidence descriptors as 

follows: 

 Carcinogenic to humans 

 Likely to be carcinogenic to humans
 

 Suggestive evidence for carcinogenicity 

 Insufficient evidence to determine carcinogenicity 

 Not likely to be carcinogenic 

IARC uses a Numeric-Alpha grouping for carcinogens (ITER, 2006) that is similar to the 1986 

U.S. EPA groupings. Exhibit 6 summarizes the IARC cancer groupings. The Health Canada 

groupings are derived from the IARC system but use Roman numerals I through V for the five 

IARC groupings (ITER, 2006). 

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Exhibit 6: IARC Cancer Groupings (ITER, 2006) 

Group Description 

1 Carcinogenic to humans 

2A Probably carcinogenic to humans 

2B Possibly carcinogenic to humans 

3 Not classifiable as to its carcinogenicity to humans 

4 Probably not carcinogenic to humans 

The data abstracted from the NTP database on cancer studies are those from studies conducted 

by both the NTP and the NCI. The NTP (2005) describes the results of the studies as: 

 Clear evidence of carcinogenicity (CE) 

 Some evidence of carcinogenicity (SE) 

 Equivocal evidence of carcinogenicity (EE) 

 No evidence of carcinogenicity (NE) 

The NTP studies are conducted using groups of male and female rats and/or mice. The results in 

both species and both sexes have separate weight-of-evidence determinations. “Clear evidence” 

in both species and both sexes is stronger evidence that a chemical could be a potential human 

carcinogen than “clear evidence” in only two species-one sex, or in two sexes-one species. Clear 

evidence is stronger than some evidence and some evidence stronger than equivocal evidence. 

EPA took these distinctions into account when partitioning chemicals based on their NTP 

categorical cancer data. 

The NCI was responsible for conducting cancer studies for the U.S. Public Health Service prior 

to the formation of the NTP. They used a simpler system (NTP, 2005) by reporting results from 

cancer bioassays as either positive (P), negative (N) or equivocal (E). The NCI findings are 

reported in the NTP database. NCI Studies were also conducted in both sexes for rats and mice. 

The studies with positive results in both species and both sexes are those that present the highest 

level of concern regarding the potential for human carcinogenicity. 

The DBP-CAN data grouping within the EPA Distributed Structure-Searchable Toxicity (DSSTox) database is a compilation of projections on carcinogenic potential, of an assortment of 

unregulated DBPs, derived from QSAR modeling and expert judgment. The chemicals are 

categorized according to the estimated probability that they will cause cancer from high (H) to 

unlikely (L) with intermediary probabilities of high moderate (HM), moderate (M), low 

moderate (LM) and marginal (Mar). 

EPA placed the qualitative and quantitative data for carcinogenicity of chemicals only in the 

upper three toxicity categories. Carcinogens are not generally considered as having low toxicity. 

The cancer screening criteria are based on USEPA, IARC, and NTP cancer groupings for 

screening rather than the cancer slope factors because many chemicals are categorized for cancer 

Page 10 of 21 
 

Exhibit 7: Partitioning of Cancer Data Based on TD50
 

Values and Weight of Evidence 

TD50 EPA IARC 

/HC NTP NCI DSS-Tox

Toxicity 

Category 1 

<0.1 Group A; 

Human 

Carcinogen 

Group 1 CE 2 species/2 

sexes; or 2 

species; or 2 

sexes 

P 2 species/2 

sexes; or 2 

species; or 2 

sexes 

H 

Toxicity 

Category 2 

0.1 -

100 

Groups B1 and 

B2; likely 

carcinogens 

Group 2A Combinations 

of CE, SE, EE, 

and NE 

Combinations 

of P, E and N 

HM 

Toxicity 

Category 3 

>100 Group C; 

Suggestive 

evidence of 

carcinogenicity 

Group 2B Combinations 

of SE, EE, and 

NE 

Combinations 

of E and N 

M and 

LM 

** Cancer data placed chemicals in only the three highest Toxicity Categories

 CE = clear evidence, SE = some evidence, EE = equivocal evidence, NE = no evidence 

P= positive, N= Negative, E = equivocal 

H = high probability, HM= high to medium probability, M = medium probability, LM = medium to 

low probability 

EPA-OGWDW Final CCL 3 Chemicals: EPA 815-R-09-007 

Screening to a PCCL August 2009 

but do not have cancer slope factors. Therefore use of the categorical data is more inclusive than 

use of slope-factor data. 

An exception to using the categorical data for the screening for the cancer endpoint is the TD50 

data. The TD50 data set includes quantitative estimates of cancer risk for some chemicals that are 

not in the other data sets, and thus they will be used in screening in cases where no categorical 

cancer data elements are available. 

EPA partitioned the cancer-related data elements in the Universe as described in Exhibit 7. 

Quantitative measures of dose-response for carcinogenicity will be used in scoring the Potency 

attribute for potential carcinogens in the PCCL to CCL process (see the PCCL to CCL Report, 

USEPA, 2009b) but not in screening at the Universe level. 

The U.S. EPA Groups D and E, “Insufficient Evidence” and “Not Likely” descriptors, as well as 

the IARC Group 3 and 4 or Health Canada Groups IV or V, are not used when partitioning the 

categorical data elements as described in Exhibit 7. The DSS-Tox, “unlikely” and TD50, “NP” 

field entries are also not used. EPA’s decision is based on the premise that low toxicity concerns 

related to low tumorigenic properties do not mean there is no systemic toxicity for a 

contaminant. In these cases, other non-cancer data were used for screening. 

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2.4 Combining the Data Elements for Screening 

As discussed in this report, there are a variety of data elements available in the Universe that can 

be used to screen for adverse health effects. To avoid favoring chemicals with rich data sets, the 

EPA evaluated all available dose-response and categorical data elements for a given chemical in 

the screening process. When each of the data elements for a given chemical is placed in the 

screening framework, the most conservative health effects category is identified. Accordingly, if 

there is just one data element that places a chemical in Toxicity Category 1 it will be categorized 

as such even if some of the other data elements for that same chemical place it a lower toxicity 

category. For example, if a chemical is classified as a 2A carcinogen by IARC it will be placed 

in Toxicity Category 2 even if its LOAEL from a different study places it in Toxicity Category 3. 

Exhibit 8 includes several examples drawn from the Universe of chemicals that have either one 

or multiple available potency data elements. The data elements used to evaluate the chemicals 

are bolded. 

Exhibit 8: Examples of Potency Data Elements for the Selected 

Chemical Drawn from the Universe 

Chemical Toxicity 

Category 1 

Toxicity 

Category 2 

Toxicity 

Category 3 

Toxicity 

Category 4

Toxicity 

Category 5 

4-Biphenylamine Group 1 TD50 

Hexane LD50 RfD-eq 

Methylazoxymethanol acetate  Group 2B 

Molybdenum oxide NTP 

3-hydroxycarbofuran LD50 

Methylenediphenol LOAEL LD50 

BMX-1 DBP-CAN 

Primiphos methyl NOAEL RfD-eq 

LOAEL 

LD50 

LOAEL 

Four of the contaminants in Exhibit 8 have more than one health effects data element. Each 

health effects data element for a chemical will be used for the screening process but the one data 

element demonstrating the highest potency in combination with its measure of occurrence will 

determine if it is selected for the PCCL. For example, 4-biphenylamine falls in Toxicity 

Category 1 because it has an IARC Group 1 classification even though its TD50 places it in 

Toxicity Category 2. Hexane falls in Toxicity Category 4 based on its LD50 value even though its 

RfD-eq value would place it in Toxicity Category 5. 

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3.0 Occurrence Data Elements 

EPA found that data elements representing a chemical’s potential to occur in drinking water vary 

greatly in terms of the occurrence factor they represent. The goal was to determine which data 

elements best represented the potential to occur in drinking water. EPA considered and evaluated 

data elements in the following categories: 

 Finished Water – measures concentration and frequency of detections 

 Ambient Water – measures concentration and frequency of detections 

 Total Releases in the Environment – measures pounds per year and number of states 

 Pesticide Application Rates – measures pounds per year and number of states 

 Production volume – measures pounds per year 

In addition to evaluating quantitative data elements, EPA also analyzed chemicals with 

descriptive data based upon their likelihood of occurring in drinking water. Examples of these 

types of chemicals include disinfection byproducts and drinking water treatment additives. The 

following sections describe the occurrence categories and how EPA utilized them in the 

development of the screening criteria. 

To analyze the occurrence data and develop the screening criteria, EPA assembled a diagnostic 

test set of approximately 200 chemicals. Some of these chemicals were selected from past CCLs 

and National Primary Drinking Water Regulations (NPDWRs), and some were randomly pulled 

from the Universe of contaminants considered for the draft CCL 3. Most of them had data on 

concentrations in water, environmental release and production, and as such constituted a 

relatively complete set of occurrence data elements. 

3.1 Finished Water Data 

Using the Universe as a starting point, EPA considered data elements that are readily available 

for chemicals in finished water. The finished water data elements are from the National 

Contaminant Occurrence Database (unregulated contaminant monitoring) Rounds 1 and 2, the 

National Inorganic Radionuclides Survey, the Unregulated Contaminant Monitoring Regulation 

monitoring, the Information Collection Rule database for DBPs, U.S. Department of Agriculture 

Pesticide Data Program (PDP), and Pesticides Pilot Monitoring Program (PPMP) (USGS and 

USEPA). 

The finished water data elements evaluated include: 

 percent of samples with detections, 

 percent of public water systems with detections, 

 median concentration of detections, 

 mean concentration of detections, and 

 maximum concentration of detections. 

The median, mean, and maximum concentration values are based on analytical detections only. 

Non-detections were not included in these concentration measure calculations. In both the data 

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sets for finished and ambient water (Section 3.2), some chemicals had no detections at any of the 

sites surveyed. Some data sets included mean, median, and maximum values whereas others 

included only one or two of the data elements. 

For screening purposes, EPA determined that the concentration data were the most appropriate 

data elements because they have a more direct relationship with dose-response than the detection 

frequency. The concentration data ranged from <0.1 g/L to >10,000 g/L. The range was 

subdivided using powers of ten. Some chemicals had finished water data available from multiple 

sources; in those cases, the highest value was used for the purposes of screening. 

Using the toxicity categories EPA arrayed 107 chemicals with finished water data based on their 

toxicity data elements and their median concentration in finished water as shown in Exhibit 9. 

This Exhibit illustrates the distribution of chemicals across the categories. EPA developed 

additional analyses that focused on the specific chemicals within the different occurrence 

categories to set the screening criteria. 

Exhibit 9: Number of Chemicals with Median Concentrations 

Distributed through the Screening Framework by Health Effects 

Category 

Health Effects Categories 

Occurrence - Finished Water - Median (μg/L) 

0­

<0.1 

0.1­

<1 

1­

<10 

10­

<100 

100­

<1,000 

1K­

<10K ≥10K Totals 

Toxicity Category 1 1 7 22 0 4 1 0 35 

Toxicity Category 2 0 5 15 8 0 0 0 28

 Toxicity Category 3 0 8 16 3 0 0 1 28

 Toxicity Category 4 0 4 6 0 1 0 1 12

 Toxicity Category 5 0 1 2 1 0 0 0 4 

Total 1 25 61 12 5 1 2 107 

Exhibit 9 shows that about 82% (87 of 107) of the chemicals with finished water data have 

median concentrations less than 10 μg/L, a concentration that is not of high concern for Toxicity 

Category 3 to Toxicity Category 5 chemicals. This grouping would have a maximum drinking 

water equivalent level (DWEL) of ≥ 40 μg/L based on an RfD of 0.001 (see Section 4.1 for 

additional information). However, these same concentrations for finished water are of greater 

concern for chemicals with Toxicity Category 1 and Toxicity Category 2 RfDs. These types of 

analyses helped EPA evaluate the effectiveness of the screening framework as a tool to separate 

chemicals of high concern from those of low concern, especially for chemicals with finished 

water data. 

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3.2 Ambient Water Data 

EPA obtained data on ambient water values from the United States Geological Survey (USGS) 

National Water Quality Assessment Program (NAWQA), the USGS National Reconnaissance of 

Emerging Contaminants (NREC), and the PPMP. The NAWQA data include all the nationwide 

data from Cycle 1 of NAWQA, which encompasses data collected from 1992 to 2001. The 

NRECs database includes occurrence data collected by the USGS Toxic Substances Hydrology 

Program from 1999 to 2001 in samples from 142 streams, 55 wells, and seven effluent samples 

from 36 states. The PPMP data includes pesticide concentrations in water, and the sampling 

methods include 178 different pesticides and degradation products. 

The ambient water data elements analyzed include: 

 percent of samples with detections, 

 percent of sites with detections, 

 median concentration of detections, 

 mean concentration of detections, and 

 maximum concentration of detections. 

As was the case for finished water, the median, mean, and maximum values are based on 

analytical detections only. Non-detections were not included in the concentration datasets. The 

subdivisions for the data were developed by first determining the range of available ambient 

water concentration data, and then partitioning the range by powers of ten. In this case, the 

concentration data ranged from <0.01 g/L (for all concentration data) to >10,000 g/L. One of 

the data sources, NREC, did not contain mean or maximum concentration data, so it was only 

represented in the percent of samples, percent of sites, and median concentrations. EPA 

developed matrices similar to Exhibit 9 for all of the ambient water data elements using the set of 

200 diagnostic chemicals. 

3.3 Environmental Release Data 

The environmental release data are those reported for 2002 from the Toxics Release Inventory 

(TRI) and the National Pesticide Use Database, as created by the National Center for Food and 

Agricultural Policy (NCFAP). The most recent version of the NCFAP database was released in 

2000, and reflects pesticide use in 1997. 

The environmental release data elements considered include: 

 total releases to the environment (lbs/yr) 

 number of states with total releases 

 pesticide application (lbs/yr) 

 number of states with pesticide application 

As was the case for the finished and ambient water data, EPA chose to use the data on the 

pounds per year released to the environment for screening rather than the number of states with 

releases. The subdivisions used for release data were developed by first determining the range of 

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release values represented by the data, and then partitioning the range based on powers of ten. In 

this case, the release data ranged from less than 10 pounds per year to greater than 10 million 

pounds per year. EPA developed matrices similar to Exhibit 9 for all of the environmental 

release data elements. 

3.4 Production Data 

The data used to assess production volume are the Toxic Substances Control Act chemical 

production volume ranges reported under the Chemical Update System/Inventory Update Rule 

(CUS/IUR). EPA used the most recent year of data available for each particular chemical. Every 

chemical on EPA’s High Production Volume list is also in the CUS/IUR data source. Therefore, 

CUS/IUR is the primary source for production data. 

CUS/IUR reports chemical production data as ranges rather than as exact values. Therefore, EPA 

chose to use those ranges as the subdivisions for the production occurrence data. The production 

data ranges from less than 10,000 lbs/yr to greater than 1 billion lbs/yr. EPA developed matrices 

similar to Exhibit 9 for all of the production data on the test set chemicals. 

3.5 Disinfection Byproducts (DBPs) and Drinking Water Treatment 

Chemicals 

EPA recognized that two groupings of chemicals have water occurrence even in cases where 

quantitative data were not available: the DBPs from the DSS-Tox data source and the treatment 

chemicals from NSF Standard 60. In many cases there were finished water data or production 

data for some of these chemicals, but some of the chemicals lacked quantitative data. Among the 

Universe of chemicals that lacked the preferred data elements, both the DBPs and treatment 

chemicals have a strong potential to be present in drinking water. Accordingly, EPA is moving 

chemicals in these two categories forward to the PCCL for further evaluation, even when limited 

health effects or occurrence information are available. 

3.6 Combining the Data Elements for Screening 

EPA selected the occurrence data elements for screening based upon their presence in the 

universe and their suitability as a screening tool. Analyses were performed to see if the 

occurrence could be correlated across the various data elements. The diagnostic chemicals were 

used for the correlation analysis since most had data for the following data elements: mean, 

median, or maximum concentrations in finished and/or ambient water, amount released to the 

environment, and production volume. The analyses with the diagnostic chemicals demonstrated a 

limited correlation across the data elements. A chemical with a high release to the environment 

did not necessarily occur in finished or ambient water at a high concentration or even have a high 

frequency of detections. As a result, EPA decided to apply the occurrence screening data 

elements in a hierarchical manner. 

Chemicals known to occur in finished or ambient water occupy the highest position in the 

hierarchy and are most representative of a chemical’s potential to occur in drinking water. 

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Environmental releases and production are less reflective of a chemical's potential to occur in 

drinking water. Accordingly, EPA selected the following hierarchy: 

Finished Water = Ambient Water > Environmental Release Data > Production Data. 

EPA also decided that when multiple values exist for the chemicals within a given component of 

the hierarchy, the most conservative would be used as the occurrence screening element. For 

example, in the case of a chemical that has finished water data and ambient water data, the 

highest available numerical concentration value would be selected as the occurrence screening 

data element. 

4.0 Criteria for Selecting a PCCL 

The last step in the screening process was to use the intersections between health effects and 

occurrence data elements to establish the criteria for moving chemicals from the Universe to a 

PCCL. EPA grouped the Universe of chemicals that had values for health effects and occurrence 

data elements using the screening framework described in Section 1.0. Because the chemicals 

would be evaluated using a hierarchical approach for their occurrence elements, separate criteria 

were developed for each of the occurrence elements. 

To test the criteria, EPA used the set of 200 diagnostic chemicals. As stated in Section 3.0, the 

set of diagnostic contaminants included some chemicals regulated through NPDWRs, some from 

past CCLs, and a few drawn from the Universe because they had fairly complete data for all of 

the occurrence data elements. The selected regulated chemicals represented the characteristics of 

chemicals that the screening process should move to the PCCL. Accordingly, the locations of 

these chemicals in the completed screening framework were used to assist in placing the barrier 

separating those chemical contaminants that would move to the PCCL from those that would not 

be further evaluated. The series of criteria are described in the following sections and 

summarized in Appendix 1. 

4.1 Finished and Ambient Water Concentration Data 

As mentioned earlier, the finished and ambient water data are those most representative of 

contaminants likely to be found in drinking water. For this reason EPA scrutinized these data 

elements more closely than the other occurrence data elements. Initially, the placement of the 

bold black line on Exhibit 10 was positioned so that it would move the regulated chemicals and 

most of the past CCL chemicals to the PCCL. Past CCL contaminants that remained in the 

Universe and did not pass on to the PCCL (fell to the gray side of the black line) were ones 

proven to be poor candidates for regulation. 

The second tool used to evaluate the position of the black line was the DWEL. The DWEL is 

calculated by multiplying the RfD in mg/kg/day by an adult body weight of 70 kg and dividing 

by a drinking water intake of 2 L/day (rounded to one significant figure). The RfD is a dose that 

is estimated to be without adverse effects for even sensitive populations. It includes a margin of 

safety in the form of a composite uncertainty factor. Most often, the uncertainty factor is a value 

of 100, 300, 1000 or 3000. For this exercise, the DWEL was derived from the lower RfD value 

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in each Toxicity Category (See Exhibit 4) and then positioned in the appropriate toxicity and 

occurrence cell of the framework. 

Since all Toxicity Category 1 contaminants are moved to the PCCL, it is the DWELs for the 

Toxicity Category 2 to Toxicity Category 5 groupings that are of interest for this analysis. The 

calculated DWELs for the four toxicity categories of interest are as follows: 

 Toxicity Category 2 – 4 μg/L 

 Toxicity Category 3 – 40 μg/L 

 Toxicity Category 4 – 2,000 μg/L 

 Toxicity Category 5 – 4,000 μg/L 

As shown in Exhibit 10 by the asterisk in the cells, three of the four DWELs fall in the drinking 

water concentration range of the first cell that moves to the PCCL. The DWEL for the Toxicity 

Category 4 grouping is one unit above the divider. This analysis combined with the positions of 

the chemicals in the occurrence test set of chemicals provided support for the position of the 

PCCL selection line for finished and ambient water. 

 

 

 

 

Exhibit 10: Criteria for Screening Health Effects and Water Categories 

Screening Health 

Effects Categories 

Occurrence – Finished Water – Concentration (g/L) 

0-<0.1 0.1-<1 1-<10 10-<100 100­

<1,000 1K-<10K ≥10K 

Toxicity Category 1 

Toxicity Category 2 * 

Toxicity Category 3 * 

Toxicity Category 4 * 

Toxicity Category 5 * 

4.2 Environmental Release Data 

EPA used total releases to the environment (TRI) and pesticide application rate data to develop 

the criteria for this category. To aid in setting the limits for the release category, EPA started 

with criteria used to develop the first CCL (CCL 1): that a chemical had to be released in 

quantities greater than 400,000 lbs/yr to surface waters. EPA found that this CCL 1 criterion was 

too stringent and only a few chemicals would have moved to the PCCL. Accordingly EPA used 

the positions of the test set chemicals to position the Universe to PCCL barrier. The criterion for 

moving a chemical with environmental release data to the PCCL is displayed in Exhibit 11. 

Chemicals with environmental releases above the non-shaded area move to the PCCL. 

Chemicals in the shaded area stay in the Universe. 

Page 18 of 21 
 

 

 

 

 

Exhibit 11: Criteria for Screening Health Effects and 

Environmental Release Categories 

Screening Health 

Effects Categories 

Occurrence – Environmental Release Category – 

Total Environmental Releases (lbs/year) 

0 - <10 10 -

<100 100 -<1K 1K -<10K 

10K -

<100K 100K<1M 1M -

<10M ≥10M 

Toxicity Category 1

 Toxicity Category 2

 Toxicity Category 3

 Toxicity Category 4

 Toxicity Category 5 

 

 

 

 

 

 

Exhibit 12: Criteria for Screening Health Effects and 

Production Categories 

Screening Health 

Effects Categories 

Occurrence - Production Category (lbs/year) 

<10K 10K500K 

>500K1M >1M10M >10M50M >50M100M >100M500M >500M 

-1B >1B

 Toxicity Category 1

 Toxicity Category 2

 Toxicity Category 3

 Toxicity Category 4

 Toxicity Category 5 

EPA-OGWDW Final CCL 3 Chemicals: EPA 815-R-09-007 

Screening to a PCCL August 2009 

4.3 Production Data 

Similar to the release category, EPA started with the criteria used to develop CCL 1 that a 

chemical be produced in quantities greater than 1 billion lbs/yr. EPA decided that the CCL 1 

guideline was too restrictive and proposed criteria that are less stringent for screening at this 

stage of the process. The criterion for moving a chemical, with production data, to the PCCL is 

displayed in Exhibit 12. Chemicals above the line move to the PCCL. Chemicals in the shaded 

areas remain in the CCL Universe. 

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4.4 DBPS and Drinking Water Additives 

The DBPs and drinking water additives that lacked quantitative occurrence data but fell in the 

Toxicity Category 1 or Toxicity Category 2 groupings based on their toxicity were added to the 

PCCL because of their high probability for being present in disinfected and treated drinking 

water. 

5.0 Efficacy of the Framework as a Screening Tool 

The proposed screening approach provides a data-driven, objective, and transparent process for 

selecting the PCCL from the Universe. Chemicals are screened based on their data elements and 

not based on their names or CAS numbers for the initial PCCL screen. All Toxicity Category 1 

chemicals are captured no matter what the occurrence data element. The occurrence threshold 

required for the PCCL selection become less inclusive as the contaminant toxicity decreases. 

Once the initial screening is complete, the names of the PCCL chemicals are apparent. After the 

initial screen, quality assurance measures were applied. EPA then conducted a detailed 

examination of decisions that placed chemicals close to the borderline. 

The screening approach on the CCL 3 Universe selected 561 chemical contaminants from the 

approximately 6,000 chemicals in the CCL 3 Universe that were screened. (This includes 

contaminant information that was compiled as part of EPA’s nominations and surveillance 

process and submitted in the public comments on the draft CCL 3.) Appendix 2 shows the 

contaminants that moved to the PCCL for additional consideration and the data used in their 

screening. 

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6.0 References 

Health Canada. 2005. What is an LD50 and LC50. Canadian Center for Occupational Health and 

Safety. Ontario Canada. Available at. http://www.ccohs.ca/oshanswers/chemicals/ld50.html
 

Hodge, H.C. and J.H. Sterner. 1956. Combined tabulation of toxicity classes. In: Spector, W.S., 

ed. Handbook of toxicology, Philadelphia, W.B. Saunders Company, Vol. 1. 

International Toxicity Estimates for Risk (ITER). 2006. ITER Definitions (Classification). 

Toxicology Excellence for Risk Assessment, Cincinnati, OH. 

Available at: http://www/iter.ctcnet.net/publicurl.glossary.html 

National Drinking Water Advisory Committee (NDWAC). 2004. CCL Classification Process. 

Report from the NDWAC to the U.S. Environmental Protection Agency Office of Ground Water 

and Drinking Water. May 19. 

National Toxicology Program (NTP). 2005. Management Status Report Produced from the NTP 

Chemtrack System. Central Data Management (EC-03) National Institute of Environmental 

Health Services, Research Triangle Park, NC. 

USEPA. 1986. United States Environmental Protection Agency. Guidelines for carcinogen risk 

assessment. Fed. Reg. 51(185):33992-34003. 

USEPA. 2005. United States Environmental Protection Agency. Guidelines for Carcinogen Risk 

Assessment. EPA/630/P-03/001B. Risk Assessment Forum, Washington, DC. 

USEPA. 2009a. Final Contaminant Candidate List 3 Chemicals: Identifying the Universe. EPA 

815-R-09-006. August 2009. 

USEPA. 2009b. Final Contaminant Candidate List 3 Chemicals: Classification of PCCL to the 

CCL. EPA 815-R-09-008. August 2009. 

USEPA. 2009c. Summary of Nominations for the Third Contaminant Candidate List. EPA-815­

R-09-011. August 2009. 

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7.0 Appendices 

Appendix 1. Criteria for Selecting the PCCL 

Contains the series of criteria used to select the PCCL from the CCL Chemical Universe. 

This criterion is based upon the following hierarchy: Concentrations in Water > Releases to 

the Environment > Production 

Concentrations in Water 

Toxicity Category 1 chemicals with any concentration 

Toxicity Category 2 chemicals with concentrations ≥ 1 g/l 

Toxicity Category 3 chemicals with concentrations ≥ 10 g/l 

Toxicity Category 4 chemicals with concentrations ≥ 100 g/l 

Toxicity Category 5 chemicals with concentrations ≥ 1000 g/l 

Releases to the Environment 

Toxicity Category 1 chemicals with any amount released 

Toxicity Category 2 chemicals with releases/application ≥ 10,000 lbs/yr 

Toxicity Category 3 chemicals with releases/application ≥ 100,000 lbs/yr 

Toxicity Category 4 chemicals with releases/application ≥ 1 M lbs/yr
 

Toxicity Category 5 chemicals with releases/application ≥ 10 M lbs/yr 

Production 

Toxicity Category 1 chemicals with any amount produced 

Toxicity Category 2 chemicals production volumes > 500,000 lbs/yr 

Toxicity Category 3 chemicals with production volumes > 10 M lbs/yr 

Toxicity Category 4 chemicals with production volumes > 50 M lbs/yr 

Toxicity Category 5 chemicals with production volumes > 100 M lbs/yr 

A1-1 
 

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Appendix 2. Chemicals Passing Screening to the PCCL 

The following table in Appendix 2 presents the CASRN, names of the contaminants listed on the 

PCCL, and the health effects and occurrence data elements that were used in their screening. The 

data elements are described in the text of this report. 

For the Health Effects Data Element, Cancer Studies NTP, the Value is shown as the National 

Toxicology Program multi-species results (NTPMSR), representing the more detailed criteria 

and data used to derive the Toxicity Screening Category. They are described in detail in the text. 

For the Occurrence data elements, the Release data may be either national TRI data or pesticide 

application data. The notation “FW/AW” indicates the data are finished or ambient water data. 

Also noted, for some pesticide degradates, data from the parent compound were used for 

screening; for some contaminants supplemental data, compiled in the nominations and 

surveillance process were also used. 

Further data and information for the contaminants are available on the Contaminant Information 

Sheets available in the CCL 3 water docket. 

A2-1 
EPA-OGWDW Final CCL 3 Chemicals: 

Screening to a PCCL

 Appendix 2

Health Effect Data Element Value Units Occurrence Data E

5989275 (d)-Limonene Cancer Studies, NTP NTPMSR Toxicity Category 2 FW/AW-Median Va

100641 (Hydroxyimino)cyclohexane Lowest Observed Adverse Effect Level (LOAEL) 17.9 mg/kg-day Toxicity Category 4 Production Volume 

630206 1,1,1,2-Tetrachloroethane Cancer Studies, NTP NTPMSR Toxicity Category 1 FW/AW-Max Value 

918003 1,1,1-Trichloropropanone Cancer Class LM Toxicity Category 3 FW/AW-Max Value 

79345 1,1,2,2-Tetrachloroethane Reference Dose (RfD) 0.00005 mg/kg-day Toxicity Category 1 FW/AW-Max Value 

75343 1,1-Dichloroethane Cancer Classification, EPA C Toxicity Category 3 FW/AW-Max Value 

119642 1,2,3,4-Tetrahydronaphthalene Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

2,860 

87616 1,2,3-Trichlorobenzene Tolerable Daily Intake (TDI) 0.0015 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

96184 1,2,3-Trichloropropane Cancer Studies, NTP NTPMSR Toxicity Category 1 FW/AW-Max Value 

95943 1,2,4,5-Tetrachlorobenzene Reference Dose (RfD) 0.0003 mg/kg-day Toxicity Category 2 Production Volume 

95636 1,2,4-Trimethylbenzene TD50 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

4,350 

122667 1,2-Diphenylhydrazine Risk Specific Dose (RSD) 0.00001 mg/kg-day Toxicity Category 1 FW/AW-Max Value 106876 1,2-Epoxy-4-(epoxyethyl)cyclohexane Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

106990 1,3-Butadiene Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

542927 1,3-Cyclopentadiene Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

113 

77485 1,3-Dibromo-5,5-dimethylhydantoin Lowest Observed Adverse Effect Level (LOAEL) 0.44 mg/kg-day Toxicity Category 2 Production Volume 

542756 1,3-Dichloropropene Cancer Studies, NTP NTPMSR Toxicity Category 1 FW/AW-Max Value 

99627 1,3-Diisopropylbenzene Lowest Observed Adverse Effect Level (LOAEL) 0.25 mg/kg-day Toxicity Category 2 Production Volume 99650 1,3-Dinitrobenzene Reference Dose (RfD) 0.0001 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

105113 1,4-Benzoquinone dioxime Cancer Studies, NTP NTPMSR Toxicity Category 2 Production Volume 

110634 1,4-Butanediol No Observed Effect Level (NOEL) 200 mg/kg-day Toxicity Category 4 Production Volume 

110656 1,4-Butynediol Lowest Observed Adverse Effect Level (LOAEL) 2 mg/kg-day Toxicity Category 3 Production Volume 

105088 1,4-Cyclohexanedimethanol Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

1,600 

123911 1,4-Dioxane Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

4904614 1,5,9-Cyclododecatriene Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

1,780 

2432997 11-Aminoundecanoic acid Cancer Studies, NTP NTPMSR Toxicity Category 2 Production Volume 

57910 17alpha-estradiol Acceptable Daily Intake (ADI) 0.00005 mg/kg-day Toxicity Category 1 FW/AW-Max Value 

81492 1-Amino-2,4-dibromoanthraquinone Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

71363 1-Butanol Lowest Observed Adverse Effect Level (LOAEL) 0.2 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

112301 1-Decanol Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

4,720 

112538 1-Dodecanol Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

1,170 

111706 1-Heptanol Lowest Observed Adverse Effect Level (LOAEL) 0.0251 mg/kg-day Toxicity Category 2 Production Volume 592416 1-Hexene Lowest Observed Adverse Effect Level (LOAEL) mg/kg-day Toxicity Category 5 Production Volume 

1,000 

71410 1-Pentanol Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

200 

71238 1-Propanol Lowest Observed Adverse Effect Level (LOAEL) 600 mg/kg-day Toxicity Category 4 Production Volume 

2439352 2-(Dimethylamino)ethyl acrylate No Observed Effect Level (NOEL) 4 mg/kg-day Toxicity Category 3 Production Volume 

96139 2,3-Dibromopropanol Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 95954 2,4,5-Trichlorophenol No Observed Adverse Effect Level (NOAEL) 0.3 mg/kg-day Toxicity Category 2 Release (lbs/yr) 88062 2,4,6-Trichlorophenol Cancer Studies, NTP NTPMSR Toxicity Category 1 FW/AW-Max Value 

105679 2,4-Dimethylphenol Reference Dose (RfD) 0.02 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

51285 2,4-Dinitrophenol Lowest Observed Adverse Effect Level (LOAEL) 0.0006 mg/kg-day Toxicity Category 1 FW/AW-Max Value 

121142 2,4-Dinitrotoluene Cancer Studies, NTP NTPMSR Toxicity Category 1 FW/AW-Max Value 

95807 2,4-Toluenediamine Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

95874 2,5-Xylenol Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

383 

576261 2,6-Dimethylphenol Reference Dose (RfD) 0.0006 mg/kg-day Toxicity Category 2 Production Volume 

87627 2,6-Xylidine Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

96297 2-Butanone oxime No Observed Effect Level (NOEL) 4 mg/kg-day Toxicity Category 3 Production Volume 

78897 2-Chloro-1-propanol Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

100 

Toxicity Screening 

Category

Health Effect/Toxicity Data Element Used For Screening Occurrence D

CASRN Common Name

A2-2
EPA-OGWDW Final CCL 3 Chemicals: 

Screening to a PCCL

 Appendix 2

Health Effect Data Element Value Units Occurrence Data E

Toxicity Screening 

Category

Health Effect/Toxicity Data Element Used For Screening Occurrence D

CASRN Common Name

645625 2-Ethyl-3-propylacrolein Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

3,000 

123057 2-Ethylhexanal Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

2,600 

149575 2-Ethylhexanoic acid Lowest Observed Adverse Effect Level (LOAEL) 885 mg/kg-day Toxicity Category 4 Production Volume 

104767 2-Ethylhexanol Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

2,053 

26266682 2-Ethylhexenal Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

2,005 

103117 2-Ethylhexyl acrylate Lowest Observed Adverse Effect Level (LOAEL) 3 mg/kg-day Toxicity Category 3 Production Volume 

7659861 2-Ethylhexyl thioglycolate Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

303 

818611 2-Hydroxyethyl acrylate Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

300 

149304 2-Mercaptobenzothiazole TD50 344 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

109864 2-Methoxyethanol Reference Dose (RfD) 0.001 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

78784 2-Methylbutane Lowest Observed Adverse Effect Level (LOAEL) 357.1 mg/kg-day Toxicity Category 4 Production Volume 

109068 2-Methylpyridine Lowest Observed Adverse Effect Level (LOAEL) 0.0099 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

91598 2-Naphthalenamine Cancer Classification, IARC 1 Toxicity Category 1 Release (lbs/yr) 

135193 2-Naphthalenol Lowest Observed Adverse Effect Level (LOAEL) 0.437 mg/kg-day Toxicity Category 2 Production Volume 

79469 2-Nitropropane Cancer Classification, EPA B2 Toxicity Category 2 Release (lbs/yr) 

127060 2-Propanone oxime TD50 12.1 mg/kg-day Toxicity Category 2 Production Volume 

107186 2-Propen-1-ol Lowest Observed Adverse Effect Level (LOAEL) 0.05 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

616455 2-Pyrrolidone Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

328 

1948330 2-tert-Butylhydroquinone Maximum Recommended Daily Dose (MRDD) 0.2 mg/kg-day Toxicity Category 2 Production Volume 

91941 3,3'-Dichlorobenzidine Risk Specific Dose (RSD) 0.000022 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

612828 3,3'-Dimethylbenzidine dihydrochloride Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

760236 3,4-Dichloro-1-butene No Observed Effect Level (NOEL) 2 mg/kg-day Toxicity Category 3 Production Volume 

3401807 3,6-Dichlorosalicylic acid Lowest Observed Adverse Effect Level (LOAEL) 3 mg/kg-day Toxicity Category 3 Production Volume 

132059531 3-Bromo-4-(dibromomethyl)-5-hydroxy-2(5H)-

furanone (BMX-3)

Cancer class only HM Toxicity Category 2 FW/AW-Max Value 

563473 3-Chloro-2-methyl-1-propene Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

132059519 3-Chloro-4-(bromochloromethyl)-5-hydroxy2(5H)-furanone (BMX-1) Cancer class only HM Toxicity Category 2 FW/AW-Max Value 

132059520 3-Chloro-4-(dibromomethyl)-5-hydroxy-2(5H)-

furanone (BMX-2)

Cancer class only HM Toxicity Category 2 FW/AW-Max Value 

16655826 3-Hydroxycarbofuran Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 FW/AW-Max Value 

7 

108996 3-Methylpyridine Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

400 

100549 3-Pyridinecarbonitrile No Observed Effect Level (NOEL) 5 mg/kg-day Toxicity Category 3 Production Volume 553264 4,4'-Bipyridine Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

172 

101804 4,4'-Diaminodiphenyl ether Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

80079 4,4'-Dichlorodiphenyl sulfone Reference Dose (RfD) 0.005 mg/kg-day Toxicity Category 3 Production Volume 

101611 4,4'-Methylenebis(N,Ndimethyl)benzenamine Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

101688 4,4'-Methylenedi(phenyl isocyanate) Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

2,200 

101779 4,4'-Methylenedianiline Lowest Observed Adverse Effect Level (LOAEL) 4.3 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

92671 4-Aminobiphenyl Cancer Classification, IARC 1 Toxicity Category 1 Release (lbs/yr) 

101542 4-Aminodiphenylamine Lowest Observed Adverse Effect Level (LOAEL) 150 mg/kg-day Toxicity Category 4 Production Volume 

95830 4-Chloro-1,2-diaminobenzene Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

5216251 4-Chlorobenzotrichloride Cancer Classification, EPA B2 Toxicity Category 2 Production Volume 

123422 4-Hydroxy-4-methyl-2-pentanone No Observed Effect Level (NOEL) 30 mg/kg-day Toxicity Category 4 Production Volume 

108112 4-Methyl-2-pentanol Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

2,600 

6610293 4-Methyl-3-thiosemicarbazide Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

14 

A2-3
EPA-OGWDW Final CCL 3 Chemicals: 

Screening to a PCCL

 Appendix 2

Health Effect Data Element Value Units Occurrence Data E

Toxicity Screening 

Category

Health Effect/Toxicity Data Element Used For Screening Occurrence D

CASRN Common Name

98533 4-tert-Butylcyclohexanone Lethal Dose 50 (LD50) mg/kg Toxicity Category 5 Production Volume 

5,000 

100403 4-Vinylcyclohexene Cancer Studies, NTP NTPMSR Toxicity Category 2 Production Volume 

95794 5-Chloro-o-toluidine Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

16219753 5-Ethylidene-2-norbornene No Observed Effect Level (NOEL) 4 mg/kg-day Toxicity Category 3 Production Volume 

99592 5-Nitro-o-anisidine Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 99558 5-Nitro-o-toluidine Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

71751412 Abamectin Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Release (lbs/yr) 2 30560191 Acephate Lowest Observed Effect Level (LOEL) 0.12 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

75070 Acetaldehyde Cancer Classification, EPA B2 Toxicity Category 2 Release (lbs/yr) 

79027 Acetaldehyde, dichloro-Dichloroacetaldehyde Cancer Class M Toxicity Category 3 FW/AW-Max Value 60355 Acetamide TD50 180 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

103902 Acetaminophen TD50 495 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

64197 Acetic acid Lowest Observed Adverse Effect Level (LOAEL) 1.47 mg/kg-day Toxicity Category 3 Production Volume 

108247 Acetic anhydride Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

1,780 

34256821 Acetochlor Reference Dose (RfD) 0.02 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

187022113 Acetochlor ethanesulfonic acid (ESA) Reference Dose (RfD) Parent data mg/kg-day Toxicity Category 3 FW/AW 

184992444 Acetochlor oxanilic acid (OA) Reference Dose (RfD) Parent data mg/kg-day Toxicity Category 3 FW/AW 

67641 Acetone No Observed Effect Level (NOEL) 100 mg/kg-day Toxicity Category 4 FW/AW-Max Value 75865 Acetone cyanohydrin Reference Dose (RfD) 0.0008 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

75058 Acetonitrile Reference Dose (RfD) 0.006 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

107028 Acrolein Reference Dose (RfD) 0.0005 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

79107 Acrylic acid No Observed Adverse Effect Level (NOAEL) 53 mg/kg-day Toxicity Category 4 Release (lbs/yr) 

107131 Acrylonitrile Risk Specific Dose (RSD) 0.000019 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

124049 Adipic acid Lowest Observed Adverse Effect Level (LOAEL) mg/kg-day Toxicity Category 5 Production Volume 

4,000 

111693 Adiponitrile Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

22 

142363539 Alachlor ethanesulfonic acid (ESA) Reference Dose (RfD) Parent data mg/kg-day Toxicity Category 2 FW/AW 

171262172 Alachlor oxanilic acid (OA) Reference Dose (RfD) Parent data mg/kg-day Toxicity Category 2 FW/AW 

309002 Aldrin Reference Dose (RfD) 0.00003 mg/kg-day Toxicity Category 1 FW/AW-Max Value 

96242 alpha-Chlorohydrin Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

26 

319846 alpha-Hexachlorocyclohexane Risk Specific Dose (RSD) 0.000002 mg/kg-day Toxicity Category 1 FW/AW-Max Value 

98851 alpha-Methylbenzenemethanol TD50 458 mg/kg-day Toxicity Category 3 Production Volume 98839 alpha-Methylstyrene Reference Dose (RfD) 0.07 mg/kg-day Toxicity Category 4 Production Volume 

834128 Ametryn Reference Dose (RfD) 0.009 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

33089611 Amitraz No Observed Effect Level (NOEL) 0.25 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

7664417 Ammonia Lowest Observed Adverse Effect Level (LOAEL) 6.2 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

1111780 Ammonium carbamate Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

681 

7783188 Ammonium thiosulfate Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

1,098 

64285069 Anatoxin-a Reference Dose (RfD) 0.0005 mg/kg-day Toxicity Category 2 FW/AW 

62533 Aniline Cancer Classification, EPA B2 Toxicity Category 2 Release (lbs/yr) 

142041 Aniline hydrochloride Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

100663 Anisole Lowest Observed Adverse Effect Level (LOAEL) 0.65 mg/kg-day Toxicity Category 2 Production Volume 

50782 Aspirin Lowest Observed Adverse Effect Level (LOAEL) 0.0021 mg/kg-day Toxicity Category 1 Production Volume 

492808 Auramine Cancer Classification, IARC 1 Toxicity Category 1 Release (lbs/yr) 

86500 Azinphos-methyl Lowest Observed Adverse Effect Level (LOAEL) 0.91 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

741582 Bensulide Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Release (lbs/yr) 271 

A2-4
EPA-OGWDW Final CCL 3 Chemicals: 

Screening to a PCCL

 Appendix 2

Health Effect Data Element Value Units Occurrence Data E

Toxicity Screening 

Category

Health Effect/Toxicity Data Element Used For Screening Occurrence D

CASRN Common Name

25057890 Bentazon Reference Dose (RfD) 0.03 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

100527 Benzaldehyde TD50 mg/kg-day Toxicity Category 3 Production Volume 

1,490 

92875 Benzidine Risk Specific Dose (RSD) 0.000000043 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

271896 Benzofuran Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

65850 Benzoic acid No Observed Adverse Effect Level (NOAEL) 34 mg/kg-day Toxicity Category 4 Production Volume 

95147 Benzotriazole Lowest Observed Adverse Effect Level (LOAEL) 0.60 mg/kg-day Toxicity Category 2 Production Volume 

98077 Benzotrichloride Risk Specific Dose (RSD) 0.0000008 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

100516 Benzyl alcohol Maximum Recommended Daily Dose (MRDD) 5 mg/kg-day Toxicity Category 3 Production Volume 

100447 Benzyl chloride Risk Specific Dose (RSD) 0.00006 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

108601 Bis(2-chloro-1-methylethyl) ether Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 111444 Bis(2-chloroethyl) ether Risk Specific Dose (RSD) 0.0000091 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

577117 Bis(2-ethylhexyl) sodium sulfosuccinate Lowest Observed Adverse Effect Level (LOAEL) 0.5 mg/kg-day Toxicity Category 2 Production Volume 

542881 Bis(chloromethyl) ether Risk Specific Dose (RSD) 0.000000045 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

80057 Bisphenol A -- BPA Lowest Observed Adverse Effect Level (LOAEL) 2.5 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

7440428 Boron Minimal Risk Level (MRL) 0.01 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

314409 Bromacil Cancer Classification, EPA C Toxicity Category 3 FW/AW-Max Value 

7726956 Bromine Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Release (lbs/yr) 440 

108861 Bromobenzene Reference Dose (RfD) 0.02 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

83463621 Bromochloroacetonitrile (BCAN) Cancer class only M Toxicity Category 3 FW/AW-Max Value 

74964 Bromoethane Cancer Studies, NTP NTPMSR Toxicity Category 2 Production Volume 

109740 Butanenitrile Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

28 

85687 Butyl benzyl phthalate Cancer Studies, NTP NTPMSR Toxicity Category 2 Production Volume 

25013165 Butylated hydroxyanisole Lowest Observed Adverse Effect Level (LOAEL) 0.25 mg/kg-day Toxicity Category 2 FW/AW-Median Va

107926 Butyric acid Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

2,000 

106310 Butyric anhydride Lethal Dose 50 (LD50) mg/kg Toxicity Category 5 Production Volume 

8,790 

6459945 C.I. Acid Red 114, disodium salt Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

2429745 C.I. Direct Blue 15 Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

28407376 C.I. Direct Blue 218 Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

2832408 C.I. Disperse Yellow 3 Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

5160021 C.I. Pigment Red 53, barium salt (2:1) Cancer Studies, NTP NTPMSR Toxicity Category 2 Production Volume 

842079 C.I. Solvent Yellow 14 Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

471341 Calcium carbonate Lowest Observed Adverse Effect Level (LOAEL) mg/kg-day Toxicity Category 5 Production Volume 

60,000 

1305620 Calcium hydroxide Lethal Dose 50 (LD50) mg/kg Toxicity Category 5 Production Volume 

7,300 

1592230 Calcium octadecanoate Lethal Dose 50 (LD50) mg/kg Toxicity Category 5 Production Volume 

10,000 

105602 Caprolactam No Observed Adverse Effect Level (NOAEL) 50 mg/kg-day Toxicity Category 4 Production Volume 133062 Captan Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

63252 Carbaryl Lowest Observed Adverse Effect Level (LOAEL) 0.23 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

10605217 Carbendazim Lowest Observed Adverse Effect Level (LOAEL) 0.59 mg/kg-day Toxicity Category 2 Production Volume 

75150 Carbon disulfide Minimal Risk Level (MRL) 0.01 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

120809 Catechol TD50 84.7 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

75694 CFC-11 Lowest Observed Adverse Effect Level (LOAEL) 349 mg/kg-day Toxicity Category 4 FW/AW-Max Value 

75718 CFC-12 No Observed Adverse Effect Level (NOAEL) 15 mg/kg-day Toxicity Category 4 FW/AW-Max Value 

302170 Chloral hydrate TD50 106 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

14866683 Chlorate Cancer Studies, NTP NTPMSR Toxicity Category 2 FW/AW-Max Value 

A2-5
EPA-OGWDW Final CCL 3 Chemicals: 

Screening to a PCCL

 Appendix 2

Health Effect Data Element Value Units Occurrence Data E

Toxicity Screening 

Category

Health Effect/Toxicity Data Element Used For Screening Occurrence D

CASRN Common Name

115286 Chlorendic acid Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

54593838 Chlorethoxyfos Lowest Observed Adverse Effect Level (LOAEL) 0.05 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

107200 Chloroacetaldehyde TD50 36.1 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

79049 Chloroacetyl chloride Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

208 

510156 Chlorobenzilate Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

75003 Chloroethane Cancer Studies, NTP NTPMSR Toxicity Category 2 FW/AW-Max Value 74873 Chloromethane (Methyl chloride) Reference Dose (RfD) 0.004 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

107302 Chloromethyl methyl ether Cancer Classification, EPA A Toxicity Category 1 Release (lbs/yr) 

25167800 Chlorophenol No Observed Adverse Effect Level (NOAEL) 0.3 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

76062 Chloropicrin Lowest Observed Adverse Effect Level (LOAEL) 32 mg/kg-day Toxicity Category 4 Release (lbs/yr) 

126998 Chloroprene Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

1897456 Chlorothalonil Cancer Studies, NTP NTPMSR Toxicity Category 1 FW/AW-Max Value 

104552 Cinnamaldehyde Lowest Observed Adverse Effect Level (LOAEL) 0.21 mg/kg-day Toxicity Category 2 Production Volume 

77929 Citric acid Maximum Recommended Daily Dose (MRDD) 100 mg/kg-day Toxicity Category 4 Production Volume 

110429624 Clethodim Acceptable Daily Intake (ADI) 0.01 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

81777891 Clomazone Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Release (lbs/yr) 1,369 

7440484 Cobalt Lowest Observed Adverse Effect Level (LOAEL) 0.04 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

Cobalt compounds Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Release (lbs/yr) 150 

91645 Coumarin TD50 13.9 mg/kg-day Toxicity Category 2 Production Volume 

1319773 Cresol Lowest Observed Adverse Effect Level (LOAEL) 177 mg/kg-day Toxicity Category 4 Release (lbs/yr) 

15096523 Cryolite Lowest Observed Adverse Effect Level (LOAEL) 23.1 mg/kg-day Toxicity Category 4 Release (lbs/yr) 

80159 Cumene hydroperoxide Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Release (lbs/yr) 382 

135206 Cupferron Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

13752517 Cure-Rite 18 TD50 90.8 mg/kg-day Toxicity Category 2 Production Volume 21725462 Cyanazine Lowest Observed Adverse Effect Level (LOAEL) 0.98 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

506774 Cyanogen chloride Reference Dose (RfD) 0.05 mg/kg-day Toxicity Category 4 FW/AW-Max Value 

108805 Cyanuric acid No Observed Effect Level (NOEL) 600 mg/kg-day Toxicity Category 4 Production Volume 

108770 Cyanuric chloride Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

350 

113136779 Cyclanilide Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Release (lbs/yr) 208 

110827 Cyclohexane Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Release (lbs/yr) 813 

108930 Cyclohexanol Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Release (lbs/yr) 1,400 

108941 Cyclohexanone No Observed Adverse Effect Level (NOAEL) 462 mg/kg-day Toxicity Category 4 Production Volume 

108918 Cyclohexylamine Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

11 

68359375 Cyfluthrin Reference Dose (RfD) 0.025 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

143545908 Cylindrospermopsin Reference Dose (RfD) 0.00003 mg/kg-day Toxicity Category 1 FW/AW 

52315078 Cypermethrin Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Release (lbs/yr) 24.6 

66215278 Cyromazine No Observed Effect Level (NOEL) 0.75 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

1861321 Dacthal Reference Dose (RfD) 0.01 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

Dacthal mono/di-acid degradate Reference Dose (RfD) Parent data mg/kg-day Toxicity Category 3 FW/AW-Max Value 

1163195 Decabromodiphenyl ether Reference Dose (RfD) 0.01 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

541026 Decamethylcyclopentasiloxane Lethal Dose 50 (LD50) mg/kg Toxicity Category 5 Production Volume 

24,134 

6190654 Desethylatrazine Reference Dose (RfD) Parent data mg/kg-day Toxicity Category 2 FW/AW 

1007289 Desisopropylatrazine Reference Dose (RfD) Parent data mg/kg-day Toxicity Category 2 FW/AW 

50997 D-Glucose Maximum Recommended Daily Dose (MRDD) 100 mg/kg-day Toxicity Category 4 Production Volume 

A2-6
EPA-OGWDW Final CCL 3 Chemicals: 

Screening to a PCCL

 Appendix 2

Health Effect Data Element Value Units Occurrence Data E

Toxicity Screening 

Category

Health Effect/Toxicity Data Element Used For Screening Occurrence D

CASRN Common Name

142223 Diallyl glycol carbonate Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

279 

7398698 Diallyldimethylammonium chloride Lowest Observed Adverse Effect Level (LOAEL) mg/kg-day Toxicity Category 5 Production Volume 

1,000 

333415 Diazinon Reference Dose (RfD) 0.00009 mg/kg-day Toxicity Category 1 FW/AW-Max Value 

Diazinon oxygen analog Reference Dose (RfD) Parent data mg/kg-day Toxicity Category 2 FW/AW 

3252435 Dibromoacetonitrile (DBAN) Cancer Studies, NTP NTPMSR Toxicity Category 1 FW/AW-Max Value 

74953 Dibromomethane Reference Dose (RfD) 0.01 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

683181 Dibutyltin dichloride Lethal Dose 50 (LD50) mg/kg Toxicity Category 1 Production Volume 

0.05 

818086 Dibutyltin oxide Lowest Observed Adverse Effect Level (LOAEL) 0.17 mg/kg-day Toxicity Category 2 Production Volume 

99309 Dichloran Acceptable Daily Intake (ADI) 0.01 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

3018120 Dichloroacetonitrile (DCAN) Cancer Class LM Toxicity Category 3 FW/AW-Max Value 

594047 Dichloroiodomethane Cancer Class M Toxicity Category 3 FW/AW-Max Value 

62737 Dichlorvos Risk Specific Dose (RSD) 0.00003 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

115322 Dicofol TD50 32.9 mg/kg-day Toxicity Category 2 Release (lbs/yr) 141662 Dicrotophos Reference Dose (RfD) 0.0001 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

77736 Dicyclopentadiene Reference Dose (RfD) 0.03 mg/kg-day Toxicity Category 3 Release (lbs/yr) 60571 Dieldrin Reference Dose (RfD) 0.00005 mg/kg-day Toxicity Category 1 FW/AW-Max Value 

111422 Diethanolamine No Observed Adverse Effect Level (NOAEL) 20 mg/kg-day Toxicity Category 4 Release (lbs/yr) 

64675 Diethyl sulfate Cancer Classification, IARC 2A Toxicity Category 2 Release (lbs/yr) 

25340174 Diethylbenzene Lowest Observed Adverse Effect Level (LOAEL) 0.64 mg/kg-day Toxicity Category 2 Production Volume 

111466 Diethylene glycol TD50 mg/kg-day Toxicity Category 3 Production Volume 

1,660 

112345 Diethylene glycol monobutyl ether Reference Dose (RfD) 0.01 mg/kg-day Toxicity Category 3 Production Volume 

111400 Diethylenetriamine Lowest Observed Adverse Effect Level (LOAEL) 10 mg/kg-day Toxicity Category 4 Production Volume 

68479981 Diethyltoluenediamine Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

472 

43222486 Difenzoquat methyl sulfate Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Release (lbs/yr) 206 

101906 Diglycidyl resorcinol ether Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

55290647 Dimethipin Reference Dose (RfD) 0.02 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

60515 Dimethoate Reference Dose (RfD) 0.0002 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

868859 Dimethyl hydrogen phosphite Cancer Studies, NTP NTPMSR Toxicity Category 2 Production Volume 

112185 Dimethyl laurylamine Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

740 

77781 Dimethyl sulfate Cancer Classification, IARC 2A Toxicity Category 2 Release (lbs/yr) 

120616 Dimethyl terephthalate Cancer Studies, NTP NTPMSR Toxicity Category 3 Production Volume 

124403 Dimethylamine Lowest Observed Adverse Effect Level (LOAEL) 0.347 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

75785 Dimethyldichlorosilane Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

800 

753731 Dimethyltin dichloride Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

73.9 

25321146 Dinitrotoluene Risk Specific Dose (RSD) 0.00001 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

122394 Diphenylamine Lowest Observed Adverse Effect Level (LOAEL) 0.83 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

142847 Dipropylamine Lowest Observed Adverse Effect Level (LOAEL) 5 mg/kg-day Toxicity Category 3 Production Volume 

25265718 Dipropylene glycol Lethal Dose 50 (LD50) mg/kg Toxicity Category 5 Production Volume 

14,850 

2764729 Diquat Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Release (lbs/yr) 30 

928723 Disodium iminodiacetate Lethal Dose 50 (LD50) mg/kg Toxicity Category 5 Production Volume 

8,070 

298044 Disulfoton Reference Dose (RfD) 0.00004 mg/kg-day Toxicity Category 1 FW/AW-Max Value 

330541 Diuron No Observed Effect Level (NOEL) 0.63 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

27176870 Dodecylbenzenesulfonic acid Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

650 

2439103 Dodine Reference Dose (RfD) 0.004 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

115297 Endosulfan No Observed Adverse Effect Level (NOAEL) 0.7 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

A2-7
EPA-OGWDW Final CCL 3 Chemicals: 

Screening to a PCCL

 Appendix 2

Health Effect Data Element Value Units Occurrence Data E

Toxicity Screening 

Category

Health Effect/Toxicity Data Element Used For Screening Occurrence D

CASRN Common Name

759944 EPTC Reference Dose (RfD) 0.025 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

517099 equilenin Acceptable Daily Intake (ADI) 0.00005 mg/kg-day Toxicity Category 1 FW/AW-Max Value 

474862 equilin Acceptable Daily Intake (ADI) 0.00005 mg/kg-day Toxicity Category 1 FW/AW-Max Value 

114078 Erythromycin Maximum Recommended Daily Dose (MRDD) 66.7 mg/kg-day Toxicity Category 4 Supp

66230044 Esfenvalerate Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Release (lbs/yr) 325 

50282 Estradiol (17-beta estradiol) Acceptable Daily Intake (ADI) 0.00005 mg/kg-day Toxicity Category 1 FW/AW-Max Value 

140670 Estragole TD50 51.8 mg/kg-day Toxicity Category 2 Production Volume 

50271 Estriol Acceptable Daily Intake (ADI) 0.00005 mg/kg-day Toxicity Category 1 FW/AW-Max Value 53167 Estrone Acceptable Daily Intake (ADI) 0.00005 mg/kg-day Toxicity Category 1 FW/AW-Max Value 

64175 Ethanol Lowest Observed Adverse Effect Level (LOAEL) 1.43 mg/kg-day Toxicity Category 3 Production Volume 

16672870 Ethephon Lowest Observed Effect Level (LOEL) 0.5 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

57636 Ethinyl Estradiol (17-alpha ethynyl estradiol) Maximum Recommended Daily Dose (MRDD) 0.0005 mg/kg-day Toxicity Category 1 FW/AW-Max Value 

563122 Ethion Reference Dose (RfD) 0.0005 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

13194484 Ethoprop Acceptable Daily Intake (ADI) 0.0004 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

141786 Ethyl acetate Maximum Recommended Daily Dose (MRDD) 25 mg/kg-day Toxicity Category 4 Production Volume 

140885 Ethyl acrylate Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

75047 Ethylamine Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

400 

107211 Ethylene glycol Tolerable Daily Intake (TDI) 0.05 mg/kg-day Toxicity Category 4 Release (lbs/yr) 111762 Ethylene glycol monobutyl ether Lowest Observed Adverse Effect Level (LOAEL) 5.1 mg/kg-day Toxicity Category 3 Production Volume 

75218 Ethylene oxide Cancer Classification, IARC 1 Toxicity Category 1 Release (lbs/yr) 96457 Ethylene thiourea Reference Dose (RfD) 0.00008 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

107153 Ethylenediamine Reference Dose (RfD) 0.09 mg/kg-day Toxicity Category 4 Production Volume 

60004 Ethylenediaminetetraacetic acid Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

30 

22224926 Fenamiphos Reference Dose (RfD) 0.00025 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

13356086 Fenbutatin oxide Acceptable Daily Intake (ADI) 0.03 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

14484641 Ferbam Acceptable Daily Intake (ADI) 0.003 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

2164172 Fluometuron Reference Dose (RfD) 0.01 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

144490 Fluoroacetic acid Lethal Dose 50 (LD50) mg/kg Toxicity Category 1 Production Volume 

0.47 

72178020 Fomesafen Risk Specific Dose (RSD) 0.00005 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

944229 Fonofos No Observed Effect Level (NOEL) 0.2 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

50000 Formaldehyde TD50 2.19 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

23422539 Formetanate hydrochloride Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Release (lbs/yr) 18 

64186 Formic acid Lowest Observed Adverse Effect Level (LOAEL) 360 mg/kg-day Toxicity Category 4 Release (lbs/yr) 

110009 Furan Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

98011 Furfural Cancer Studies, NTP NTPMSR Toxicity Category 2 Production Volume 

96480 gamma-Butyrolactone Lowest Observed Adverse Effect Level (LOAEL) 160.7 mg/kg-day Toxicity Category 4 Production Volume 

7440564 Germanium Lowest Observed Adverse Effect Level (LOAEL) 0.32 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

111308 Glutaraldehyde Lowest Observed Adverse Effect Level (LOAEL) 0.3 mg/kg-day Toxicity Category 2 Production Volume 

56815 Glycerine Maximum Recommended Daily Dose (MRDD) 999 mg/kg-day Toxicity Category 4 Production Volume 

556525 Glycidol Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

107222 Glyoxal Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

200 

74975 Halon 1011 Reference Dose (RfD) 0.01 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

75887 HCFC-133a TD50 87.3 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

75456 HCFC-22 Lowest Observed Adverse Effect Level (LOAEL) 13.5 mg/kg-day Toxicity Category 4 Release (lbs/yr) 

142825 Heptane Lowest Observed Adverse Effect Level (LOAEL) mg/kg-day Toxicity Category 5 Production Volume 

2,857 

A2-8
EPA-OGWDW Final CCL 3 Chemicals: 

Screening to a PCCL

 Appendix 2

Health Effect Data Element Value Units Occurrence Data E

Toxicity Screening 

Category

Health Effect/Toxicity Data Element Used For Screening Occurrence D

CASRN Common Name

87683 Hexachlorobutadiene Reference Dose (RfD) 0.0002 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

67721 Hexachloroethane Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

4719044 Hexahydro-1,3,5-tris(2-hydroxyethyl)-striazine Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

1.99 

111499 Hexahydroazepine Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

20.7 

822060 Hexamethylene-1,6-diisocyanate Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

350 

124094 Hexamethylenediamine Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

750 

100970 Hexamethylenetetramine Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

569 

110543 Hexane Reference Dose (RfD) 0.06 mg/kg-day Toxicity Category 4 Release (lbs/yr) 

2691410 HMX Lowest Observed Adverse Effect Level (LOAEL) 0.99 mg/kg-day Toxicity Category 2 Production Volume 

302012 Hydrazine Risk Specific Dose (RSD) 0.0000033 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

7647010 Hydrochloric acid Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

900 

6386385 Hydrocinnamic acid, 3,5-di-tert-butyl-4-

hydroxy-, methyl ester

Lowest Observed Adverse Effect Level (LOAEL) 600 mg/kg-day Toxicity Category 4 Production Volume 

7783064 Hydrogen sulfide Reference Dose (RfD) 0.003 mg/kg-day Toxicity Category 3 Production Volume 

123319 Hydroquinone TD50 82.8 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

868779 Hydroxyethyl methacrylate Lowest Observed Adverse Effect Level (LOAEL) 2.50 mg/kg-day Toxicity Category 3 Production Volume 

13463406 Iron pentacarbonyl Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Release (lbs/yr) 12 

78831 Isobutanol Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

74.1 

115117 Isobutene Cancer Studies, NTP NTPMSR Toxicity Category 3 Production Volume 

110190 Isobutyl acetate Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

4,763 

78820 Isobutyronitrile Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

25 

29590429 Isooctyl acrylate Lethal Dose 50 (LD50) mg/kg Toxicity Category 5 Production Volume 

5,000 

121915 Isophthalic acid Lethal Dose 50 (LD50) mg/kg Toxicity Category 5 Production Volume 

10,400 

78795 Isoprene Cancer Studies, NTP NTPMSR Toxicity Category 2 Production Volume 67630 Isopropanol Lowest Observed Adverse Effect Level (LOAEL) 18 mg/kg-day Toxicity Category 4 Production Volume 

625558 Isopropyl formate Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

1.4 

75310 Isopropylamine Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

111 

6846500 Kodaflex txib No Observed Effect Level (NOEL) 30 mg/kg-day Toxicity Category 4 Production Volume 

77501634 Lactofen Reference Dose (RfD) 0.002 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

78977 Lactonitrile Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

31 

91465086 lambda-Cyhalothrin Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Release (lbs/yr) 56 

1335326 Lead acetate Cancer Classification, EPA B Toxicity Category 2 Production Volume 

330552 Linuron Lowest Observed Effect Level (LOEL) 0.63 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

554132 Lithium carbonate Lowest Observed Adverse Effect Level (LOAEL) 0.017 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

7447418 Lithium chloride Lowest Observed Adverse Effect Level (LOAEL) 0.009 mg/kg-day Toxicity Category 1 Production Volume 

121755 Malathion No Observed Effect Level (NOEL) 0.23 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

108316 Maleic anhydride Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Release (lbs/yr) 390 

123331 Maleic hydrazide Lowest Observed Effect Level (LOEL) 500 mg/kg-day Toxicity Category 4 Release (lbs/yr) 

109773 Malononitrile Reference Dose (RfD) 0.0001 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

12427382 Maneb Reference Dose (RfD) 0.005 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

94746 MCPA Reference Dose (RfD) 0.0005 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

108394 m-Cresol Cancer Classification, EPA C Toxicity Category 3 Release (lbs/yr) 

541731 m-Dichlorobenzene Minimal Risk Level (MRL) 0.03 mg/kg-day Toxicity Category 3 FW/AW-Max Value 108781 Melamine Cancer Studies, NTP NTPMSR Toxicity Category 2 Production Volume 

24307264 Mepiquat chloride Reference Dose (RfD) 0.03 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

A2-9
EPA-OGWDW Final CCL 3 Chemicals: 

Screening to a PCCL

 Appendix 2

Health Effect Data Element Value Units Occurrence Data E

Toxicity Screening 

Category

Health Effect/Toxicity Data Element Used For Screening Occurrence D

CASRN Common Name

68111 Mercaptoacetic acid Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

114 

150505 Merphos Reference Dose (RfD) 0.00003 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

72333 Mestranol Maximum Recommended Daily Dose (MRDD) 0.00083 mg/kg-day Toxicity Category 1 FW/AW-Max Value 

79390 Methacrylamide Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

451 

79414 Methacrylic acid Lowest Observed Adverse Effect Level (LOAEL) 5 mg/kg-day Toxicity Category 3 Production Volume 

126987 Methacrylonitrile Reference Dose (RfD) 0.0001 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

10265926 Methamidophos Reference Dose (RfD) 0.00005 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

67561 Methanol Lowest Observed Adverse Effect Level (LOAEL) 3.1 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

3268493 Methional Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

1.52 

16752775 Methomyl Lowest Observed Adverse Effect Level (LOAEL) 0.1 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

59052 Methotrexate Lowest Observed Adverse Effect Level (LOAEL) 0.00435 mg/kg-day Toxicity Category 1 FW/AW-Max Value 79209 Methyl acetate Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

3,705 

96333 Methyl acrylate Reference Dose (RfD) 0.03 mg/kg-day Toxicity Category 3 Release (lbs/yr) 74839 Methyl bromide (Bromomethane) Reference Dose (RfD) 0.001 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

598550 Methyl carbamate Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

74931 Methyl mercaptan Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

61 

80626 Methyl methacrylate Lowest Observed Adverse Effect Level (LOAEL) 0.36 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

1634044 Methyl tert-butyl ether Tolerable Daily Intake (TDI) 0.01 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

74895 Methylamine Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

100 

12108133 Methylcyclopentadienyl manganese 

tricarbonyl

Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

8 

93152 Methyleugenol Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

4553622 Methylglutaronitrile Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

10 

75796 Methyltrichlorosilane Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

800 

9006422 Metiram Acceptable Daily Intake (ADI) 0.03 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

51218452 Metolachlor Cancer Classification, EPA C Toxicity Category 3 FW/AW-Max Value 

171118095 Metolachlor ethanesulfonic acid (ESA) Reference Dose (RfD) Parent data mg/kg-day Toxicity Category 3 FW/AW 

152019733 Metolachlor oxanilic acid (OA) Reference Dose (RfD) Parent data mg/kg-day Toxicity Category 3 FW/AW 

21087649 Metribuzin Lowest Observed Adverse Effect Level (LOAEL) 0.62 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

101043372 Microcystin-LR Reference Dose (RfD) 0.000003 mg/kg-day Toxicity Category 1 FW/AW 

2212671 Molinate No Observed Effect Level (NOEL) 0.2 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

7439987 Molybdenum Lowest Observed Adverse Effect Level (LOAEL) 0.14 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

1313275 Molybdenum trioxide Cancer Studies, NTP NTPMSR Toxicity Category 3 Release (lbs/yr) 

105555 N,N'-Diethylthiourea Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

127195 N,N-Dimethylacetamide Maximum Recommended Daily Dose (MRDD) 0.58 mg/kg-day Toxicity Category 2 Production Volume 

108010 N,N-Dimethylethanolamine Maximum Recommended Daily Dose (MRDD) 15 mg/kg-day Toxicity Category 4 Production Volume 

300765 Naled No Observed Effect Level (NOEL) 0.2 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

91203 Naphthalene Cancer Studies, NTP NTPMSR Toxicity Category 1 FW/AW-Max Value 

123864 n-Butyl acetate Lethal Dose 50 (LD50) mg/kg Toxicity Category 5 Production Volume 

14,000 

97881 N-Butyl methacrylate Lowest Observed Adverse Effect Level (LOAEL) 3.57 mg/kg-day Toxicity Category 3 Production Volume 

126307 Neopentyl glycol No Observed Effect Level (NOEL) 100 mg/kg-day Toxicity Category 4 Production Volume 

7440020 Nickel Cancer Classification, IARC 1 Toxicity Category 1 FW/AW-Max Value 

Nickel compounds Cancer Classification, IARC 1 Toxicity Category 1 Release (lbs/yr) 

7440031 Niobium Cancer Classification, EPA A Toxicity Category 1 Production Volume 

139139 Nitrilotriacetic acid Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

98953 Nitrobenzene Reference Dose (RfD) 0.0005 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

A2-10
EPA-OGWDW Final CCL 3 Chemicals: 

Screening to a PCCL

 Appendix 2

Health Effect Data Element Value Units Occurrence Data E

Toxicity Screening 

Category

Health Effect/Toxicity Data Element Used For Screening Occurrence D

CASRN Common Name

1836755 Nitrofen Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

55630 Nitroglycerin Lowest Observed Adverse Effect Level (LOAEL) 0.008 mg/kg-day Toxicity Category 1 Release (lbs/yr) 75525 Nitromethane Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

872504 N-Methyl-2-pyrrolidone Lowest Observed Adverse Effect Level (LOAEL) 120 mg/kg-day Toxicity Category 4 Release (lbs/yr) 

924425 N-Methylolacrylamide Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

55185 N-Nitrosodiethylamine (NDEA) Risk Specific Dose (RSD) 0.00000007 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

62759 N-nitrosodimethylamine (NDMA) Reference Dose (RfD) 0.000008 mg/kg-day Toxicity Category 1 FW/AW 

924163 N-Nitroso-di-n-butylamine (NDBA) Risk Specific Dose (RSD) 0.000002 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

621647 N-Nitroso-di-n-propylamine (NDPA) Risk Specific Dose (RSD) 0.000001 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

86306 N-Nitrosodiphenylamine Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

10595956 N-Nitrosomethylethylamine (NMEA) Risk Specific Dose (RSD) 0.0000004 mg/kg-day Toxicity Category 1 FW/AW 

684935 N-Nitroso-N-methylurea TD50 0.093 mg/kg-day Toxicity Category 1 Release (lbs/yr) 930552 N-nitrosopyrrolidine (NPYR) Risk Specific Dose (RSD) 0.000005 mg/kg-day Toxicity Category 1 FW/AW 

68224 Norethindrone (19-Norethisterone) Maximum Recommended Daily Dose (MRDD) 0.0167 mg/kg-day Toxicity Category 2 Fails screen

27314132 Norflurazon Reference Dose (RfD) 0.04 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

103651 n-Propylbenzene Lowest Observed Adverse Effect Level (LOAEL) 2.5 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

88733 o-Chloronitrobenzene Reference Dose (RfD) 0.001 mg/kg-day Toxicity Category 3 Production Volume 

95498 o-Chlorotoluene Reference Dose (RfD) 0.02 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

556672 Octamethylcyclotetrasiloxane Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

1,540 

20325400 o-Dianisidine dihydrochloride Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

528290 o-Dinitrobenzene Reference Dose (RfD) 0.0001 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

88722 o-Nitrotoluene Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

95534 o-Toluidine Cancer Classification, IARC 2A Toxicity Category 2 Release (lbs/yr) 

636215 o-Toluidine hydrochloride Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

19666309 Oxadiazon No Observed Effect Level (NOEL) 0.5 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

75569 Oxirane, methyl- Risk Specific Dose (RSD) 0.000042 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

301122 Oxydemeton-methyl Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Release (lbs/yr) 10 

42874033 Oxyfluorfen No Observed Effect Level (NOEL) 0.3 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

10028156 Ozone TD50 1.9 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

72559 p,p'-DDE Risk Specific Dose (RSD) 0.000029 mg/kg-day Toxicity Category 1 FW/AW-Max Value 

4685147 Paraquat Lowest Observed Adverse Effect Level (LOAEL) 0.93 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

100005 p-Chloronitrobenzene TD50 473 mg/kg-day Toxicity Category 3 Production Volume 

106434 p-Chlorotoluene Reference Dose (RfD) 0.02 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

120718 p-Cresidine Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 100254 p-Dinitrobenzene Reference Dose (RfD) 0.0001 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

32534819 Pentabromodiphenyl ethers Reference Dose (RfD) 0.002 mg/kg-day Toxicity Category 3 Production Volume 

76017 Pentachloroethane Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

115775 Pentaerythritol No Observed Effect Level (NOEL) 100 mg/kg-day Toxicity Category 4 Production Volume 

3296900 Pentaerythritol dibromide Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

110623 Pentanal Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

5.66 

14797730 Perchlorate No Observed Effect Level (NOEL) 0.007 mg/kg-day Toxicity Category 1 FW/AW-Max Value 

52645531 Permethrin No Observed Effect Level (NOEL) 5 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

335671 Perfluorooctanoic acid (PFOA) Lowest Observed Adverse Effect Level (LOAEL) 1.0 mg/kg-day Toxicity Category 2 FW/AW 

1763231 Perfluorooctane sulfonic acid (PFOS) Lethal Dose 50 (LD50) 251.0 mg/kg Toxicity Category 3 Production Volume 

77098 Phenolphthalein Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

101848 Phenyl ether Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

2,450 

A2-11
EPA-OGWDW Final CCL 3 Chemicals: 

Screening to a PCCL

 Appendix 2

Health Effect Data Element Value Units Occurrence Data E

Toxicity Screening 

Category

Health Effect/Toxicity Data Element Used For Screening Occurrence D

CASRN Common Name

62384 Phenylmercury acetate Reference Dose (RfD) 0.00008 mg/kg-day Toxicity Category 1 Production Volume 57410 Phenytoin TD50 59.1 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

732116 Phosmet Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Release (lbs/yr) 26 

7723140 Phosphorus Reference Dose (RfD) 0.00002 mg/kg-day Toxicity Category 1 FW/AW-Max Value 

88993 Phthalic acid Lowest Observed Adverse Effect Level (LOAEL) 0.56 mg/kg-day Toxicity Category 2 Production Volume 

110894 Piperidine Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

22.4 

156105 p-Nitrosodiphenylamine Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

99990 p-Nitrotoluene Reference Dose (RfD) 0.01 mg/kg-day Toxicity Category 3 Production Volume 

26062793 Poly(dimethyl diallyl ammonium chloride) Lowest Observed Adverse Effect Level (LOAEL) 290 mg/kg-day Toxicity Category 4 Production Volume 

7440097 Potassium Lowest Observed Adverse Effect Level (LOAEL) 0.94 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

156434 p-Phenetidine Lowest Observed Adverse Effect Level (LOAEL) 0.24 mg/kg-day Toxicity Category 2 Production Volume 

41198087 Profenofos Lowest Observed Adverse Effect Level (LOAEL) 0.05 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

1610180 Prometon Reference Dose (RfD) 0.015 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

107120 Propanenitrile Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

35.8 

2312358 Propargite Reference Dose (RfD) 0.02 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

107197 Propargyl alcohol Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Release (lbs/yr) 20 

123386 Propionaldehyde Cancer Classification, DSSTOX LM Toxicity Category 3 Release (lbs/yr) 

79094 Propionic acid Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

1,640 

1639607 Propoxyphene hydrochloride Lowest Observed Adverse Effect Level (LOAEL) 0.0013 mg/kg-day Toxicity Category 1 Production Volume 

57556 Propylene glycol Lowest Observed Adverse Effect Level (LOAEL) 5 mg/kg-day Toxicity Category 3 Production Volume 

107982 Propylene glycol 1-methyl ether Reference Dose (RfD) 0.7 mg/kg-day Toxicity Category 5 Production Volume 

108656 Propylene glycol monomethyl ether acetate No Observed Effect Level (NOEL) 300 mg/kg-day Toxicity Category 4 Production Volume 

57018527 Propylene glycol mono-t-butyl ether Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

1698608 Pyrazon Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Release (lbs/yr) 493 

110861 Pyridine Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

2176627 Pyridine, pentachloro- Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

435 

14808607 Quartz (SiO2) Cancer Classification, IARC 1 Toxicity Category 1 Production Volume 

91225 Quinoline Risk Specific Dose (RSD) 0.0000033 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

76578126 Quizalofop Reference Dose (RfD) Surrogate data mg/kg-day Toxicity Category 2 Release (lbs/yr) 

121824 RDX (Hexahydro-1,3,5-trinitro-1,3,5-triazine) Risk Specific Dose (RSD) 0.00009 mg/kg-day Toxicity Category 1 Production Volume 

793248 Santoflex 13 No Observed Effect Level (NOEL) 6 mg/kg-day Toxicity Category 3 Production Volume 

135988 sec-Butylbenzene Lowest Observed Adverse Effect Level (LOAEL) 4.42 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

74051802 Sethoxydim No Observed Effect Level (NOEL) 8.9 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

7440213 Silicon Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 FW/AW-Max Value 

3,160 

7440235 Sodium Lowest Observed Adverse Effect Level (LOAEL) 9.4 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

26628228 Sodium azide Lowest Observed Adverse Effect Level (LOAEL) 0.25 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

532321 Sodium benzoate Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

1,600 

7647156 Sodium bromide Lowest Observed Adverse Effect Level (LOAEL) 0.13 mg/kg-day Toxicity Category 2 Production Volume 

7775099 Sodium chlorate Lowest Observed Adverse Effect Level (LOAEL) 1.4 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

3926623 Sodium chloroacetate Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

95 

128041 Sodium dimethyldithiocarbamate Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Release (lbs/yr) 300 

25155300 Sodium dodecylbenzenesulfonate Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

438 

62748 Sodium fluoroacetate Reference Dose (RfD) 0.00002 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

A2-12
EPA-OGWDW Final CCL 3 Chemicals: 

Screening to a PCCL

 Appendix 2

Health Effect Data Element Value Units Occurrence Data E

Toxicity Screening 

Category

Health Effect/Toxicity Data Element Used For Screening Occurrence D

CASRN Common Name

7681529 Sodium hypochlorite Lowest Observed Adverse Effect Level (LOAEL) 2.2 mg/kg-day Toxicity Category 3 Production Volume 

137428 Sodium methyldithiocarbamate Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Release (lbs/yr) 50 

1313822 Sodium sulfide Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

205 

13718268 Sodium vanadate Lowest Observed Adverse Effect Level (LOAEL) 0.62 mg/kg-day Toxicity Category 2 Production Volume 

50704 Sorbitol Maximum Recommended Daily Dose (MRDD) 833 mg/kg-day Toxicity Category 4 Production Volume 

131929607 Spinosyn A Acceptable Daily Intake (ADI) 0.02 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

57114 Stearic acid Lowest Observed Adverse Effect Level (LOAEL) mg/kg-day Toxicity Category 5 Production Volume 

1,490.5 

7440246 Strontium No Observed Adverse Effect Level (NOAEL) 190 mg/kg-day Toxicity Category 4 FW/AW-Max Value 

7782992 Sulfurous acid Lowest Observed Adverse Effect Level (LOAEL) 0.5 mg/kg-day Toxicity Category 2 Production Volume 

2699798 Sulfuryl fluoride Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Release (lbs/yr) 100 

35400432 Sulprofos Lowest Observed Adverse Effect Level (LOAEL) 0.6 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

1934210 Tartrazine Lowest Observed Adverse Effect Level (LOAEL) 0.014 mg/kg-day Toxicity Category 2 Production Volume 

107534963 Tebuconazole Acceptable Daily Intake (ADI) 0.03 mg/kg-day Toxicity Category 3 Release (lbs/yr) 112410238 Tebufenozide Acceptable Daily Intake (ADI) 0.02 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

34014181 Tebuthiuron No Observed Effect Level (NOEL) 7 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

13494809 Tellurium Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 FW/AW-Max Value 

20 

13071799 Terbufos Reference Dose (RfD) 0.000025 mg/kg-day Toxicity Category 1 FW/AW-Max Value 

56070167 Terbufos sulfone Reference Dose (RfD) Parent data mg/kg-day Toxicity Category 1 FW/AW 

56070156 Terbufos-O-analogue sulfone Reference Dose (RfD) Parent data mg/kg-day Toxicity Category 1 FW/AW-Max Value 

100210 Terephthalic acid Lowest Observed Adverse Effect Level (LOAEL) 142.5 mg/kg-day Toxicity Category 4 Production Volume 

75650 tert-Butanol TD50 64.6 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

75912 tert-Butyl hydroperoxide Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

320 

75649 tert-Butylamine Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

44 

98066 tert-Butylbenzene Lowest Observed Adverse Effect Level (LOAEL) 4.42 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

78002 Tetraethyl lead Reference Dose (RfD) 0.0000001 mg/kg-day Toxicity Category 1 Production Volume 

116143 Tetrafluoroethene Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

109999 Tetrahydrofuran Cancer Studies, NTP NTPMSR Toxicity Category 2 FW/AW-Max Value 

75570 Tetramethylammonium chloride Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

50 

75592 Tetramethylammonium hydroxide Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

34 

64028 Tetrasodium EDTA Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

2,000 

25265774 Texanol Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

3,200 

79277671 Thifensulfuron Reference Dose (RfD) Surrogate data mg/kg-day Toxicity Category 3 Release (lbs/yr) 

2231574 Thiocarbazide Lethal Dose 50 (LD50) mg/kg Toxicity Category 2 Production Volume 

6 

59669260 Thiodicarb Acceptable Daily Intake (ADI) 0.03 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

23564058 Thiophanate-methyl No Observed Effect Level (NOEL) 8 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

108985 Thiophenol Reference Dose (RfD) 0.00001 mg/kg-day Toxicity Category 1 Production Volume 

137268 Thiram Reference Dose (RfD) 0.005 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

7440291 Thorium-232 Cancer Classification, EPA A Toxicity Category 1 FW/AW-Max Value 

26471625 Toluene diisocyanate Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 66841256 Tralomethrin No Observed Effect Level (NOEL) 0.75 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

75967 Tribromoacetic Acid (TBAA) Cancer Class LM Toxicity Category 3 FW/AW-Max Value 

78488 Tribufos Reference Dose (RfD) 0.00003 mg/kg-day Toxicity Category 1 Release (lbs/yr) 

1461229 Tributyltin chloride Lethal Dose 50 (LD50) mg/kg Toxicity Category 1 Production Volume 

0.03 

545062 Trichloroacetonitrile Cancer Class LM Toxicity Category 3 FW/AW-Max Value 

A2-13
EPA-OGWDW Final CCL 3 Chemicals: 

Screening to a PCCL

 Appendix 2

Health Effect Data Element Value Units Occurrence Data E

Toxicity Screening 

Category

Health Effect/Toxicity Data Element Used For Screening Occurrence D

CASRN Common Name

102716 Triethanolamine TD50 100 mg/kg-day Toxicity Category 3 Production Volume 121448 Triethylamine Lowest Observed Adverse Effect Level (LOAEL) 1 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

112276 Triethylene glycol Lowest Observed Adverse Effect Level (LOAEL) 3.6 mg/kg-day Toxicity Category 3 Production Volume 

1582098 Trifluralin No Observed Effect Level (NOEL) 0.75 mg/kg-day Toxicity Category 2 FW/AW-Max Value 

552307 Trimellitic anhydride Lethal Dose 50 (LD50) mg/kg Toxicity Category 4 Production Volume 

1,900 

512561 Trimethyl phosphate Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 

75503 Trimethylamine Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

397 

77996 Trimethylolpropane Acceptable Daily Intake (ADI) 0.05 mg/kg-day Toxicity Category 4 Production Volume 

118967 Trinitrotoluene Reference Dose (RfD) 0.0005 mg/kg-day Toxicity Category 2 Production Volume 101020 Triphenyl phosphite Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

444 

76879 Triphenyltin hydroxide (TPTH) Acceptable Daily Intake (ADI) 0.0005 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

126727 Tris(2,3-dibromopropyl) phosphate Cancer Studies, NTP NTPMSR Toxicity Category 1 Release (lbs/yr) 

140089 Tris(2-chloroethyl) phosphite Lethal Dose 50 (LD50) mg/kg Toxicity Category 3 Production Volume 

100 

115968 Tris(chloroethyl)phosphate Cancer Studies, NTP NTPMSR Toxicity Category 1 FW/AW-Median Va

1120214 Undecane No Observed Effect Level (NOEL) 100 mg/kg-day Toxicity Category 4 Production Volume 

57136 Urea Lowest Observed Adverse Effect Level (LOAEL) 200 mg/kg-day Toxicity Category 4 Production Volume 

51796 Urethane TD50 16.9 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

7440622 Vanadium Reference Dose (RfD) 0.007 mg/kg-day Toxicity Category 3 FW/AW-Max Value 

1314621 Vanadium pentoxide Cancer Studies, NTP NTPMSR Toxicity Category 1 Production Volume 1929777 Vernolate Reference Dose (RfD) 0.001 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

50471448 Vinclozolin Reference Dose (RfD) 0.025 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

108054 Vinyl acetate TD50 341 mg/kg-day Toxicity Category 3 Release (lbs/yr) 

75025 Vinyl fluoride Cancer Classification, IARC 2A Toxicity Category 2 Production Volume 

25013154 Vinyltoluene Reference Dose (RfD) 0.006 mg/kg-day Toxicity Category 3 Production Volume 

137304 Ziram TD50 10.7 mg/kg-day Toxicity Category 2 Release (lbs/yr) 

A2-14