### Federal Register / Vol. 57, No. 12 / Friday, January 17, 1992 / Proposed Rules

ENVIRONMENTAL PROTECTION
AGENCY

40 CFR Parts 704 and 799 [OPPTS-42038A; FRL 3883-41
RIN:2070-AbO7
ArylPhosphate Base Stocks; Proposed Test Rule Including Reporting and Recordkeeplng Requirements

AGENCY: Environmental Protection 

### Agency (EPA). ACTION: Proposed rule.

SUMMARY: EPA proposes that 

### manufacturers, importers and processors ofchemical substances in the category of aryl phosphate base stocks be required, under section 4 of the Toxic Substances Control Act (TSCA), to conduct testing. Forthis Proposed Rule, aryl phosphate base stocks are phosphate esters or combination of
esters resulting fromthe reaction ofa phenol, mixtures ofphenols, or a combination ofalkyl-substituted phenols or,in some cases, phenols plus

an alcohol, with phosphorus oxychloride (POCl3) orother phosphoric acid derivatives. This definition includes triaryl and mixed aryl/alkyl esters (whereone or two ofthe three ester groups are alkyl). Base stocks are initially manufactured arylphosphates from which other aryl phosphate products are produced, and are often commercially available. The proposed testingincludes chemical analysis and, at certain production volumes, chemical fate and health and environmental effects. This is a category rule to which every substance fitting the above definition would be subject. EPA is also proposing, under TSCA section 8(a), that manufacturers and importers ofaryl phosphate base stocks be required to report to EPA the volume of substances manufactured and imported, in accordance with 40 CFR part 704, to allow EPA to determine when certain tests are to be performed. This ruleis being proposed under the authority of TSCA sections 4(a)(1)(A) and (B), 8(a), and 26(c)(2). This rule requires that testingbe conducted to develop data with respect to health and environmental effects forwhich there is an insufficiency ofdata and experience and which are relevant to a determination that the manufacture, distribution in commerce, processing,
use, or disposal ofsuch substances or mixture, or that any combination ofsuch activities, does or does not present an unreasonable risk ofinjury to health or the environment.

DATES: Submit written comments on or before April 16, 1992. Ifpersons request

an opportunity to submit oral comments by April 1,1992, EPA will hold a public meeting on this proposed rule in Washington, DC. For information on arranging to speak at the meeting, see Unit VII ofthis preamble.

ADDRESSES: 

### Submit written comments, identified by the document control number OPPTS-42038A, in triplicate, to: TSCA Public Docket Office (TS-793),

rm. NE-G004, Office ofPollution Prevention and Toxics, Environmental Protection Agency, 401 M St., SW., Washington, DC 20460. A public version ofthe administrative record supporting this action (with confidential business information deleted) is available for inspection at the above address from 8

a.m. to 12 noon, and 1p.m. to4 p.m. Monday through Friday except legal holidays.

FOR FURTHER INFORMATION CONTACT: David Kling, Acting Director, Environmental Assistance Division (TS-- 799), Office ofPollution Prevention and Toxics, Environmental Protection Agency, rm. E-543B,401 M St., SW., Washington, DC 20460, (202) 554-1404, TDD (202) 554-0551.

SUPPLEMENTARY INFORMATION: Under section 4(a) ofTSCA, EPA shall, by rule, require testing ofa chemical substance

or mixture (substance) to develop health

or environmental data ifthe Administrator makes certain findings described inTSCA under section 4(a)(1)(A) or (B). Detailed discussion of the TSCA section 4 findings are provided in EPA's first and second proposed test rules, which were published in the Federal Registers of July 18, 1980 (45 FR 48524) and June 5, 1981 (46 FR 30300). The aryl phosphate category proposed for chemical analysis, chemical fate, environmental effects and health effects testing includes any chemical fitting the category definition in this proposal that islisted now or in the future in public or confidential portions of the TSCA section 8(b) Inventory ofChemical Substances.

EPA is also proposing, under TSCA section 8(a), that manufacturers and importers ofthese substances report annual production and/or importation volumes. This information will be used by EPA to trigger testing at levels predetermined by EPA.

The aryl phosphates are a complicated category ofchemicals that present unique factors to consider in developing an appropriate test rule. EPA expects to seriously weigh all alternative approaches and may promulgate a test rule that is substantially different from today's proposal.

I. Introduction

This rule requires manufacturers of aryl phosphate base stocks to analyze them chemically and test them for chemical fate, environmental and health effects. The testing requirements are divided into two stages. Stage one is to determine the chemical identity ofthe base stocks being produced during the period this rule is in effect. Stage one testing requires chemical analysis of base stocks by gas chromatography/

mass spectrometry (GC/MS). All manufacturers ofaryl phosphate base stocks must perform stage one testing on each base stock they manufacture and report the results to EPA. Since these analytical data may be unique to each manufacturer's product they can not be jointly developed. EPA will use these data to determine equivalency oftest substances for stage two testing. Manufacturers ofbase stocks EPA judges to be equivalent may jointly
sponsor stage two testing.

Stage two testing is to determine the chemical fate, environmental effects and health effects ofaryl phosphates. To minimize the economic impact ofthe rule, stage two testing is divided into three levels based upon the annual production volume ofthe base stock. Aryl phosphate base stocks produced at

or above 1 million pounds per year are subject to level one testing requirements. Level one consists of 120- day post-hatch rainbow trout early life stage testing (ELS), three hen 

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neurotoxicity assays, and a twogeneration reproductive effects study. Level two testing is triggered by a production volume of 5 million pounds

orhigher. It includes anaerobic biodegradation, chronic Daphnia, and subchronic toxicity testing.Aryl phosphate base stocks produced at or above 10 million pounds would be subject to level three testing. Level three includes aerobic biodegradation, microcosm effects, developmental toxicity, and the subchronic rat neurotoxicity battery.

To determine ifbase stocks have met the trigger levels, EPA isproposing a section 8(a) reporting requirement. EPA would notify manufacturers when the production triggers were met.

A. Definitions "aryl phosphate" for this proposed rule is a phosphate triester ofphenol or ofan alkyl-substituted phenol. This definition includes triaryl and mixed aryl alkyl esters (where one ortwo of the three ester groups are alkyl), and

can denote structurally unique substances, base stocks, or downstream products.

"Aryl phosphate base stock" means the phosphate ester or combination of
esters resulting from thereaction ofa phenol, mixtures ofphenols, or,in some cases, phenols plus an alcohol, with phosphorus oxychloride (POCL}or other phosphoric acid derivatives (see Unit I.C.1 ofthis preamble for a fuller discussion). This definition includes triaryl and mixed aryl/alkyl esters (where one or two of the three ester groups are alkyl). Thisreaction can produce a near-pure triaryl phosphate such as triphenyl phosphate (when phenol is used), a mix ofaryl phosphates (aswhen a mix ofan alkylphenol and phenol isused] or a mix ofisomeric esters such as ortho-, metaand paracresyl phosphates. Mono and dicresyl esters would also bepossible reaction products in the latter example. Base stocks are initially manufactured aryl phosphates from which other aryl phosphate products are produced and

are often commercially available. The base stock components remain unreacted in these aryl phosphate products. Thus, when an aryl phosphate product is released into the environment, the base stock components in the product are released into the environment. Likewise, when humans

are exposed to aryl phosphate products, they are exposed to the base stock components that are in the products. "Chemical" means any organic or inorganic substance of a particular molecular identity. 

### "Complex substance" means a "chemical substance" as definedunder section 3ofTSCA that is composed of related chemicals produced as

..... a result ofa chemical reaction." Most aryl phosphate base stocks, as defined in this proposal, are complex substances. Thenames ofthese substances generally refer to the major component.

"Component" and "constituent" are used Interchangeably, and mean one of the individually identified chemicals that, together with other components, comprise a complex substance.

"Feedstocks" are alcohols orphenols used in the manufacture ofaryl phosphate base stocks. They may be single or mixed alcohols.

"Isomer" means one of two ormore chemical compounds containing the

same numbers of atoms ofthe same elements, but differing in structural arrangement. For example, triorthocresyl phosphate (TOCP], with its methyl substituent at the ortho position ofthe phenyl group, is one ofthree pure tricresyl phosphate isomers (the others being the tri-meta and tri-para isomers).

"Mixture" is defined in TSCA section 3(8). In the case ofaryl phosphate products, a mixture includes combinations oftwo ormore aryl phosphate base stocks,or ofan aryl phosphate base stock and other chemicals, but does notinclude those defined in this proposed rule as "complex substances".

"Product" means the final commercially manufactured substance. It may be a single base stock, a mixture ofdifferent base stocks or a mixture ofa base stock with an unrelated substance. The product Phosflex 370, for example, is a mixture ofthe base stocks isodecyl diphenyl phosphate and tert-butylphenyl diphenyl phosphate.

"Substituent" means an atom orgroup that replaces another atom orgroup in a molecule. In xylol (dimethylphenol), two hydrogens ofthe phenyl moiety are replaced by two methyl substituents.

B.Background

1.ITCdesignation.The Interagency Testing Committee (ITC) designated the aryl phosphate category for priority testing consideration in its second report.The reasons for thisdesignation

are discussed in the Federal Register of April 19, 1978 (43FR 16684).



### The ITCdefined the category as "**phosphate esters of phenol orof alkyl-substituted phenols. Tri-aryl and mixed alkyl and aryl esters are included, buttri-alkyl esters are excluded." The ITCrecommended testing for "carcinogenicity, mutagenicity, teratogenicity, other chronic effects, environmental effects and epidemiology."

2.

Advance Notice of Proposed Rulemaking(ANPR)-a.Summary.The Agency published an ANPR on aryl phosphates on December 29, 1983 (48FR 57452), following discussions with the Industry Ad Hoc Aryl Phosphate Ester Committee (IAPEC}. The ANPR proposed testing nine aryl phosphate complex substances because they had been "identified by industry as being constituents ofcommercial products currently inproduction."

The nine substances proposed for testing in the ANPR were: (1)Tricresyl phosphate (TCP}, mixed isomers (tritolyt phosphate, CAS Nos. 1330-78-5 and 68952-35-2); (2)Trixylenyl phosphate 

### (TXP), mixed isomers (trixylyl phosphate, CAS Nos. 25155-23-1 and 68952-33-0); (3)Triphenyl phosphate (TPP) (CAS No. 115-86-6); (4) Nonylphenyl diphenyl phosphate (NDP), mixed isomers (CAS No. 38638-05-0); (5) 

### Dimethylbenzylphenyl diphenyl phosphate, mixed isomers (CAS No. 34364-42-6); (6] Isopropylphenyl 

### diphenyl phosphate (IPP), mixed isomers (CAS No. 28108-99-8); (7) tert

### Butylphenyl diphenyl phosphate (BDP), mixed isomers (CAS No. 56803-37-3); (8) Isodecyl diphenyl phosphate (IDP} (CAS No. 59800-46-3); (9) 2-Ethylhexyl diphenyl phosphate (EDP) (CAS No. 1241-94-7). All were base stocks as defined in this proposed rule.

The ITCdesignated these chemicals because they were ".. produced in 

### [aggregate] quantities exceeding 65 million pounds/year," NIOSH had estimated exposure ofover 2million workers, and certain members ofthis chemical class had known toxicities.

Testingproposed for aryl phosphates in the ANPR included: chronic effects

- 90-day subchronics; mutagenicity--all substances for some aspect of mutagenicity; oncogenicity (triggeredby mutagenicity ordata from the 90-day subchronics); teratogenicity for TCP, and forTXP, IPP,BDP, IDP, and EDP if triggered by TCP; reproductive effects for TCP and others if triggered by TCP results; 90-day subchronic neurotoxicity for TCP and TXP; environmental effects

- field monitoring studies, tissue residue analyses ofbiota exposed to water and sediment collected from sites known to contain aryl phosphates at measurable levels and testing on terrestrial organisms. Epidemiology studies were not considered for proposal in the ANPR.

b. Comments.EPArequested comments on eight issues in the ANPR, and received comments from eight

sources: IAPEC, five corporations (Ciba2139

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### Proposed Rules

Geigy, Eastman Kodak, FMC, Monsanto, Stauffer), the Environmental Defense Fund (EDF), and D. Muir ofthe Canadian Fisheries and Wildlife Service. Summaries ofthe issues and
comments submitted and the Agency's
response to each appear below.

1. Issue.EPA requested information

on persons exposed to aryl phosphates from synthetic feedstocks, the type of
exposure, notable changes in production ofindividual substances over the last 5
years, new applications planned for any ofthese substances and projected growth rate over the next 5 years.

Comments.The IAPEC commented that aryl phosphate production reflects a "mature product category and market growth rate isprojected below GNP levels." It stated thatproduction declined between 1979 and 1982, and that EPA should use this production decline when predicting the future trend. IAPEC estimated that fewer than 200 workers are involved in production. It

was also exploring a "user survey to address possible concerns" (the Agency has not received any such survey to date). Eastman Kodak Company and FMC also commented about the reduced production. Kodak commented on the lack ofjustification for a 4(a)(1)(B) finding.Stauffer Chemical Company commented that fewer than 90 ofits employees are exposed to aryl phosphates and that downstream worker exposure is insignificant. Stauffer also estimated exposure levels ofless than 1.0 partper billion (ppb)to air-borne aryl phosphates during each working day. Stauffer estimated that dermal exposure ocou's during less than 20 percent of the day,and thatthis is 

### minimized byprotective clothing worn by its employees. Stauffer also commented that low vaporpressure (typically <0.1 mm Hg at 100 F] of listed arylphosphates reduces the potential for inhalation exposure to an insignificant level under typical 

### operating conditions.

EPA Response.The ANPR gave levels ofprojected production in 1980 as 100 to 140 millon pounds. Manufacturers subsequently submitted production levels ofindividual substances to EPA

as confidential business information (CBI). However, EPA's current estimate ofaggregate category production, 72.1 million pounds, is available (Ref. 6).

A 1986EPA report provided information indicating that, although the production levels ofindividual aryl phosphates dipped to an all-time low in 1982, they subsequently grew 10 percent

or more by 1984 (Ref. 38). Information in the Partial Inventory Update Rule (Chemical Update System, CUS) (Ref, 69) shows that, in 1986,levels were 

### down from the highs mentioned in the ITC report, but not to the extent that manufacturers were predicting. According toEPA's assessment, production of this category remains substantial. There has,however, been a reduction in production ofsome individual base stocks listed in this proposed rule.

IAPEC commented that only about 200 workers are exposed. However, this reference was to manufacturing workers only. Many more workers are exposed while using the end product(s). The 1980 National Occupational Hazard Survey (NOHS) update shows more than 2 million workers may be exposed to aryl phosphates (Ref.51). Itis difficult to evaluate exposure numbers in subsequent data, e.g., the National Occupational Exposure Survey (NOES) (Ref.52), because ofinconsistent reporting terminology.

For purposes ofreporting to the TSCA section 8(b) Chemical Inventory, EPA allows manufacturers ofa complex substance to report it as such or as its individual components. This makes it difficultto ensure acquisition ofall the information relating to the complex substance. Forexample, NOES [Ref.52) shows 69 workers exposed to IPP(CAS No. 2810-99-8), one of the substances listed in the ANPR. However, NOES also shows 46,948 workers exposed to "isopropylated phenol,phosphate (3:1)" (CasNo. 68937-41-7), a complex substance that may contain varying amounts ofisopropylphenyl diphenyl phosphate (IPP),bis(isopropylphenyl) phenyl phosphate, and/or tris(isopropylphenyl) phosphate. depending upon the degree of propylation required for the desired end properties.

Exposure in the workplace occurs via dermal contact and inhalation. EPA estimates inhalationexposure ofTPP may be as high as 150mg/day (Ref.35). The 1986-1987 issue oftheAmerican Conference ofGovernmental Industrial Hygienists (ACGIH)Threshold Limit Values reference book (Ref.3)listed two aryl phosphates, TPP and TOCP. ACGIH recommends a time-weighted average (TWA)threshold limit value {TLV) of3 mg/ms (cubic meters) for TPPin air, and

aTWA TLVof0.1 mg/m for akin contact with TOCP.Most arylphosphate base stocks are liquids with high boiling points,but they may bevolatile orform

an aerosol in certain applications. For example, a NIOSH walkthrough ofa General Motors Die Cast Department In Rochester, NY, in which aryl phosphatecontaining hydraulic fluids were used at 100 °F,found TPP and [PPin the air at 0.57 and 0.013 milligram (mg)/cubic
meter (ml, respectively (Ref.75,). Aircraft maintenance workers may have frequent dermal contact with hydraulic fluids containing aryl phosphate base stock&. EPA estimates such exposure to be in the 1300 to 3900 mg/day range ifno protective clothing is

worn (Ref. 35). EPA described this
exposure pattern in itsproposed test rule for tributyl phosphate (TBP) (Ref. 71). EPA believes exposure level estimates for users ofaircraft hydraulic fluids containing TBP are applicable to

users ofthose containing aryl phosphate base stocks.

2.Issue.Would analytical data from the manufacturers ofcommercial TCP showing the TOCP level of their commercial product, when combined with the results ofEPA's proposed 90- day subchronic neurotoxicity study using three dose levels ofTOCP, enable the Agency to reasonably determine or predict the neurotoxicity of a TCP commercial product? Comments.EDF recommended subchronic testing of TOCP and the TCP mixture, while [APEC and Stauffer mentioned the difficulty and expense of testing pure isomers and suggested testing products instead. Stauffer discussed the use of acute toxicity and percent ortho-cresol as an acceptable neurotoxicity approximation rather than the subchronic test. Stauffer also mentioned a 7-dose-level TOCP toxicity study published in conjunction with the Delayed Neurotoxicity Workshop it recently co-sponsored. EPA Response.EPA is not proposing toxicity testing ofpure TOCP atthis time, but is proposing the produced base stock which may or maynot include TOCP. EPA did consider the multi-dose study ofTOCP (Ref. 56 and 57): however, published data on the test substance and methodology do not give enough information for EPA assessment.

The ANPR also stated that a 90-day subchronic test ofTOCP, then under
way as a positive control to FMC's 90- day study ofIPP,was not an appropriate neurotoxicity test for TCP because it

was only a single-dose study. The testing scheme discussed in the ANPR would have required a full 3-dose study ofTOCP. The FMCTOCP study received in 1986,.although a 2-dose study, was therefore still unacceptable (Ref.24).

Studies performed on individual tricresyl phosphate isomers indicated the major neurotoxicant was TOCP (Ref. 63). Manufacturers, therefore, endeavored to reduce the TOCP content oftheir products. However, a -recent TSCA section 8(e) submission 4ReL 40) indicates TOCP-reduced tiess than D.1 percent) products have neurotoxic 

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effects on the hen similar to those arising fromexposure to pure TOCP.

EPA believes aryl phosphate testing shouldfocus, at this time, on the complex substances to which people may be exposed. This proposed rule would require testing ofbase stocks, but
notindividual chemical constituents or product mixtures (see UnitI.C.3 of this preamble for fuller discussion oftest substances]. Thus,for isopropylated phenyl phosphates, three base stocks

are proposed fortesting: isopropylphenyl diphenyl-, bis(isopropylphenyl) phenyl-, and tris(isopropylphenyl) phosphate. Each of these base stocks contains smaller but significant amounts ofone orboth ofthe other isopropylated phenyl phosphates. EPA would use testdata obtained on base stocks to help determine whether

ornot testing individual constituents would be necessary.

3.Issue.Does the potential for human exposure to certain consumer products %,ontaining acutely neurotoxic TXP components warrant subchronic neurotoxicity testing?

Comments.EDF commented that all organophosphates should be tested for subchronic neurotoxicity, notjust those selected on thebasis ofacute data.It specifically suggested testing ofIPP and TXP. IAPEC stated that "the neurotoxicity ofTXPhas been determined," and that ". human 

### exposure is insignificant. As commercial production continues to decline, no further testing iswarranted." Stauffer commented that subchronic testing would be appropriate ifexposure were significant, but in any case, an acute test should be performed to determine if subchronic testing is necessary.

EPA Response.EPA believes that acute organophosphorus induced delayed neuropathy (OPIDN) testing combined with acute neurotoxic
esterase testing is a valid predictor for the OPIDN syndrome. The subchronic testing isprimarily forrisk assessment purposes.

EPA does not believe the neurotoxicity ofTXP has been adequately determined, and is proposing testing of this complex substance in this testrule. In the case ofIPP, the ANPR did not discuss possible subchronic neurotoxicity testing because, at the time, FMC was planning a 90-day subchronic assay ofIPP in the hen that

was expected toreasonably predict or determine IPPneurotoxicity. However, the data FMC submitted to EPA characterizing the composition ofthe
test material was insufficient for evaluation ofthe study (see Unit II.C.2 of this preamble). 4.Issue. Is TOCP the only agent responsible for the suggested reproductive and teratogenic effects of TCP? Should it be tested separately? Do the existing data for TOCP provide sufficient evidence to implicate other aryl phosphates?

Comments.EDF said all aryl phosphates should be tested. The IAPEC tookthe position that because no scientific data indicate TOCP or tricresyl phosphates have reproductive

or developmental effects, there is no justification for further testing. It stated that because five important commercial arylphosphates were negative in teratogenicity studies, there was no need for further testing. Stauffer stated that the information on TOCP did not justify any type ofreproductive or developmental toxicity testing. The
company asserted that validity of seminiferous tubule degeneration observed in a study ofmale rabbits and dogs with TCP (Ref. 14] mustbe questioned. Without knowing what was tested, it is difficult to draw any meaningful conclusions. Finally, Stauffer stated testing TOCP had no relevance to predicting the effect ofexposure to compounds in commercial production.

EPA Response.EPA is not proposing testing ofany component, including TOCP, ofany ofthe complex substances in this test rule. EPA agrees with Stauffer that testing single components ofan aryl phosphate is not appropriate
at this time, and instead proposes testing ofactual manufactured aryl phosphate base stocks (see Unit I.C.3 of this preamble).

The data IAPEC referred to included minimal chemical analysis on the products tested and is oflimited use for
assessment ofhazard potential.

Three recent studies have demonstrated the reproductive toxicity ofTCP in several species and strains of laboratory animals 

### (Refs. 12. 13, and 15). The National Toxicology Program (NTP) and National Institute ofEnvironmental Health Sciences (NIEHS) studies both used TCP with less than 0.1 percent TOCP, while the TCP in the EPA study contained less than 9 percent TOCP. All three studies showed effects on male reproductive parameters, and histopathologic effects were seen in the ovaries in the EPA-sponsored study. Both the EPA-sponsored and NIEHSsponsored studies demonstrated developmental toxicity, while the NIEHS study also showed effects in the F, generation at the lowest dose. A confidential TSCA section 8(e) study

was submitted to EPAin 1990 demonstrating similar reproductive effects with an additional aryl phosphate. 5. Issue.Is it possible to reduce the testing burden by forming subcategories ofsimilar aryl phosphates or by testing

a subset that spans the structural spectrum ofthe aryl phosphates category? Comments.EDF stated that information about possible toxicity of these compounds was insufficient to justify such approaches. Kodak suggested a decision to choose subcategories should be based on quantities being manufactured and potential exposure, and itwould be inappropriate for EPA to decide this

matter until these data were available. IAPEC stated that structural subsets could be developed ifa need for further testing was demonstrated, and added there was no need to conduct separate
tests for each chemical.

EPA Response.EPA has decided not
to pursue these possibilities for aryl phosphates at this time. The use of subcategories or subsets fortesting implies that the results ofsuch surrogate testing would be valid for all the chemicals not tested. EPA is not convinced there is a sufficient understanding at this time ofthe relationship ofstructure and observed toxicity to subcategorize aryl phosphate base stocks fortesting.

6. Issue.EPA sought comments on criteria used to evaluate the industrysponsored monitoring study. These included: (i)Detection limit sensitivity; (ii) quality assurance evaluation; (iii) location and selection of sampling sites; (iv) statistical treatment ofdata obtained; (v) analytical method; and (vi) interpretation ofresults.
Comments.IAPEC commented on the six criteria as follows:

a.Detectionlimitsensitivity.IAPEC contends the monitoring study they submitted demonstrates adequate margins ofsafety, and while recoveries

were variable for experimental field spikes, standard laboratory spiking and storage showed good recoveries.

b. Qualityassurance evaluation.Their quality assurance (QA) effort, which involved spiking samples from all aquatic strata tested, was sound and provided valid QA for the environmental monitoring program. IAPEC contends that EPA's concern as to the insufficiency ofa 29 percent recovery for "the phosphate esters spiked or sediment samples carried to the field and spiked in the field" is inappropriate. This description referred
to early testing involving only six samples, whereas the overall experimental recovery rate was 70 percent. 

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c.Lnctinand seetionof sampling sites.Sample site selection was agreed
upon by industry andEPA, the collections were conducted exactly as agreed upon, and calculated safety factors for each site (based on rainbow
trout MATC) ranged from 2 to 10.

d.Statisticaltreatmentof data obtained.Q-test was used to identify
extraneous or outlying values in the
water data set.All ofthe monitoring data were given to the Agency, including the raw data from the appendices of the monitoring report. Thus the Agency can apply whatever statistical treatment it considers appropriate.

e.Analyticalmethod.All methods

were validated according to state-of-theart validation procedures. Information

on methods, detection limits and quality

assurance was provided to the Agency before the program began. IAPEC received no cmments, questions or suggestions for changes.

f. Interpretation of

results.This study provides evidence forno concern for
exposure through the water column. IAPEC believes that aryl phosphates would be adsorbed to sediment and desorb very slowly, meaning that any potential enironmental problems would be to sediment-dwelling organisms. EPA Response.EPA is not proposing monitoring in this test rule.

Following the ANPR, EPA conducted

a Good Laboratory Practices (GLP) Inspection/Study Audit Report on the aryl phosphate monitoring study '(Ref. 68), which reported numerous GLP compliance deviations and reporting inconsistencies. In addition, while overall experimental recovery rate was 70percent, the recovery for the fieldspiked sediments was only 29 percent. The minimum recovery specified by the ACS guidelines forreliability (Ref. 2a) is 60 percent. A lower recovery could result in a large occurrence offalse negative results.These shortcomings caused EPA todismiss the monitoring report.

7. Issue.Howuseful is a site-specific aquatic ecotoxicity test procedure compared to standard laboratory ecological tests? Is there a need for terrestrial testing in addition to aquatic testing for a site-specific effect? Comments. IAPEC commented that a site-specific test was not feasible, because in their monitoring study, five ofthe esters proposed for testing were not found in water, fourwere not found in sediment and three were notpresent in sediment or water. in addition,where aryl phosphates were found,the
presence of'otherorganic contaminants would dominate any effects ofaryl phosphates. IAPECheld that conventional risk assessment using standardized protocols was preferae. It also contended terrestrial organism testing was not needed, as therewas no significant exposre.

EPA Response EPA is not proposing site-specific aquatic ecotoxicity testing in this test rule. EPA agrees with the

comment on testingprocedures. This proposed test rule includes standards for environmental testing and chemical fate studies. There has been some evidence ofterrestrial exposure, particularly in the vicinity of aryl phosphate manufacturing plants (Ref. 18), but EPA isnot proposing terrestrial testing at this time.

8. Issue.Should an oncogenicity testingrequirement be based on results ofselected mutagenicity tests or rather

on a section 4(a)(1)(B) finding? Comments.EDF concluded the use of mutagenicity data as the sole basis 'for choosing chemicals for oncogenicity testing was inappropriate, and stated that any chemical with substantial human exposure should be tested for oncogenicity and in vitroand in viva mutagenicity. YAPEC and Stauffer doubted aryl phosphate exposure would support a section 4(a)(1)(B)finding, and IAPEC suggested that, because all mutagenicity information was negative, oncogenicity testing should not be considered.

EPA Response.NTP is performing a 2-year bioassay on TCP,and EPA will examine the results before deciding whether further oncopenrcity esting on any other aryl phosphate isneeded.

C.Substancesto Which theRule Applies

1. Chemistryofaryl phosphates.Aryl phosphate base sock&, as defined in Unit L.A ofthis preamble, are phosphate
esters ofphenol or ofalkyl-substituted phmnols. They are produced byreaction of aphenol, alkylated phenol, and/or an aliphatic alcohol with phosphorus oxychioride (POCI6) at elevated temperatures inthe presence ofa catalyst. Mixed aryl phosphate esters

are produced by reacting fOCI, with controlled quantities of appropiate phenols. Variations in feedstock, starting proportions orreaction conditions willresult in batch-to-batch differences that couldaccount for disparities in the physical properties of these mixed esters (Refs. 42 and'50).

A second alkyl substituent inthe starting phenol greatly increases the number ofpossible components in the final product; there aremore than ,0for trixylyl (tris-dimethylphenyl) phosphate, for exampile. When the feedstock is a mixture ofnon-isomeric phenols. the possibilities may multiply even further. The

### names applied to aryl phosphate base stocks can be confusing. For example, as described inUnit i.A ofthis preamble, a pheny4 group can be alkylated in the ortho, meta, orpars position, so that "tricresyl phopi-ate [tritolyl phosphate, trimethylphenyll phosphate] could be either tri-metacresyl phosphate (TMCP)(oneofthe isomers), the corresponding triortho- (TOCP)or tri-para- (TPCP) ester, ora mixed esterwhere two orthree ofthe cresyl isomers are present in the same molecule. In practice, because commercial TCPmay be manufactured from a blend ofortho, meta, and paracresol, it may contain up to 10 possible tricresyl phosphates, in proportions that depend not only on the proportions of starting cresol isomers,but also on their relative reactivity under the manufacturing conditions employed. Socalled "tricresyl phosphate" is a complex substance containing TOCP TMCP, and TPCP (though certain commercial mixtures may be primarily the para isomerwith Ipercent or less of the ortho isomer), plus some dicresyl phenyl phosphate, cresyl diphenyl phosphate, and triphenylphosphate that reflect the presence of some unsubstituted phenol in the feedstock. I the complex substance is primarily TOCP, but contains someTMCPand TPCP, it isgenerally called TOCP.

2. Category. Under TSCA section 26, EPAhas authority totake any action authorized or required tobe taken wit respect to a chemical substance or mixture with respectto a category of substances ormixtures. TSCA section 26(c)(Z) defines "category of chemical substances" to mean

a group ofchemical substances the members ofwhich are similar in molecular structure, inphysical, chemical, or biological properties, in use, orin mode ofentrance into the human body orinto the environment, or themembers ofwhich are in someother way suitable for classffication as such for purposes ofthis Act,except that such term does not mean a group ofchemical substances which 'are groupedlogether solely

on the basis oftheirbeingnew chemical substances. Thus, the term '!category of chemical substances" is quitebroad.

This proposed rulewould require testing ofthe arylphesphate base stock category under sections 41a)(1)[A)end (B) ofTSCA for both existing members ofthe category and future entries toit. The category is based on chemical
structure. EPA believes that the phosphotriester function common to al aryl phosphates justifies using toxicity data identffying a hazard for one aryl phosphate substance to stggest ahazard potential for other aryl phosphate 

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category members. In evaluating the testing needs for the arylphosphate base stock category, EPA considered all available data, including: production volume: ue; release: exposure; test data; information included in the ITC's report; TSCA section 8[a), (d) and (e) data; comments received following the publication of the ANPR; recent publications in the literature; any EPAgenerated monitoring; and additional information.

EPA, by taking the category approach, will assure that any newlymanufactured aryl phosphate base stock meeting the category definition, such as chemicals on the TSCA Inventory but
not being produced, or any aryl phosphate base stocks that are "new chemical substances" under TSCA section 5, would also be subject to the rule. This approach should preclude the necessity of a new test rule ifchanges in production processes yield differences in aryl phosphate components.

For instance, in a 1984 report byMuir (Ref. 50), cresyl diphenyl phosphate (CAS No. 26444-49--5) was given as the major component in two commercial phosphate esters, and the 1980-81 NOES (Ref.52) reported 13,370 employees exposed tothis substance. However, although this substance is on the TSCA Inventory,no production was reported in the 1986Chemical Update System (CUS). Without the category finding, cresyl diphenyl phosphate production could easily be resumed without the substance being subject to testing.

3. Testsubstances.Promulgating a testrule foraryl phosphates raises several important policy issues. One of the most difficult isthe question ofwhat
to test. Data may be difficult or impossible to evaluate ifthe test substances are not appropriately chosen and their composition not adequately specified.

EPA considered several different test substance options: individual isomers, aryl phosphate componerts ofbase stocks listed on the inventory, aryl phosphatebase stocks, and commercial products.

a.Individualisomers.Because most aryl phosphate base stocks marketed

are complex substances whose components may have varying toxicities, EPA considered requiring testing ofeach isomeric component. The Agency abandoned this approach because ofthe diversity ofsome complex substance such as trixylenyl phosphate, which may have 50 or more isomers. The cost andcomplexity of testing hundreds of isomers wouldbe prohibitive, and the time required for such testing would significantly delay EPA's evaluation of the data. b.Basestock componenrts.The 1077 TSCA Non-Confidential Inventory includes 58 individual base stock components meeting the chemical definition (Ref.55). Several ofthe 58 aryl phosphates on the inventory are components ofthe base stocks listedin this proposed test rule but are not reported in production. Although the number ofinventory components is substantially less than the number of possible isomers, the same obiections (high cost and testing program delays) apply. In addition,the benefits ofsuch testing may be even fewer then for testing ofindividual isomers if the toxicity ofaryl phosphates is an isomerspecific phenomenon.

c. Commercial products. EPA also rejected testing of commercial aryl phosphate products. These may be aryl phosphate base stocks or mixtures of aryl phosphate base stocks and other substances. Since EPA is interested in aryl phosphate toxicity it does not seem wise to test substances that may contain non-aryl phosphate components orthat

are mixtures ofbase stocks. In addition, the number, and often the complexity, of commercial products exceeds that of base stocks, makhig this a more expensive option.

d.Basestocks.EPA is proposing aryl phosphate base stocks as the test substances. EPA believes that this approach strikes a balance between the need to characterize aryl phosphate toxicity, the unacceptably high cost of the other options considered, and the potential difficulties ofany case-by-case
test substance selection process.Base stocks, as defined in ths proposed rule, include all the individual aryl phosphates to which people or the enviromnent may be eiosed as arestt of activities involving aryl phosphate base stocks or downstream aryl phosphate-containing consumer or industrial products. Finally, iftest results ona base stock suggest a need for more detailedcharacterization, EPA

canrequire by separate rulemaking testing ofindividual or combined aryl phosphates, guided bythe analytical date and other results an all the base stocks initiallytested. Thus, this proposed rule can be considered a type ofscreening rue.

The aryl phosphate base vtocksnow in production include seven ofthe Win aryl phosphates listed in the ANPR -(see Unit I.B.2.a ofthis preamble). The other two, NDP and DBDP, are not being produced (Ref.55) and thus would not be subject to thetesting requirements unless production resumed. The more recent additions tothe listofin

### production category members m da

- butyl) phenyl phosphate (DBP), and four aryl phosphate base stocks closely related to IDP andBP.

Thus, the Agency has identified 12 members of the aryl phosphate base stock category that itbelieves to be in production (Ref.55] for which it is proposing testing at this time.They are

as follows (seeUnit 111.B ofthis preamble for more information):

i.tort-Butylphenyl diphenyl phosphate.
ii. bis-1twe-Butyhenylj phenyl phosphate. iii. tris-(tert-Butylphweyl)phosphate. iv. Di-n-butyl phenyl phosphate.

v. 2-Ethyihexyl diphenyl phosphate. vi. isodecyl dipheayl phospohate. vii.Isopropylphenyl diphenyl phosphate. viii.bis-Ilsopropylphenyl) pheny phosphate.

ix. tris.(Isopropylphenyl) phosphate.

x.Tricresyl phosphate. xi.Triphenyl phosphate. xii. Trixylyl phosphate.

4. TSCA section8(a)reportingand triggering oftesting.EPA recognizes
costs ofthe oomplete testing for some category members may be burdensome (see Unit V ofthis preamble) and has prioritized theproposed test requirements (see Unit IIH ofthis preamble). EPA believes most or all
current manufacturers ofbase stocks

can afford the tests inLevel 1, some can support the additional tests inLevel 2, and a few can afford Level 3 testing. For this reason, EPA proposes a trigger mechanism that tiestesting requirements to specified production levels.

To facilitate this approach, EPA is proposing, under section B(a) ofTSCA, a Preliminary Assessment Information Rule (PAIR)to require annual reporting by manufacturers and importers of production and importation volumesfor all substances meeting the definition of this chemicalcategory which are now.

orbecome, listedon the public or confidential portion of the TSCA Chemical Substances Inventory.

5.Synergismandantoeonisrm Synergism and antagonism among components may also affect the toxicity ofthe final product.Toscme extent this will be reflected in the tating ofbase stocks however, testih expressly for these phenomena would requiretests of individual components and combinations ofcomponents at different levels.The prohibitive costoftesting components individually (Unit I.C.3.a of this preamlie) would also apply to any study ofsynergism and antagonism.

II.F'ndings

EPA is basing itsproposed testing for members ofthe aryl phoophate category

on the authority ofsections 4(a)I(A) II IIII I I III I I I I I I ! II I 

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and 4(a)(1)(B) ofTSCA through the use ofTSCA section 26(c).


### A. FindingsUnderTSCA Section 

## 4(a)(1)(B)(i)

Pursuant to section 4(a)(1)(B) of TSCA,EPA finds that aryl phosphate base stocks are produced in substantial quantities and that the use ofaryl phosphate base stocks may result in substantial human exposure and/or substantial release to the environment.

Under TSCA section 26(c), EPA
proposes to make a section 4(a)(1)(B) finding forthe entire arylphosphate base stock category, including (1) all such substances on the TSCA Inventory, both public and confidential, and (2)any substance not yetproduced that would fit the definition ofaryl phosphate base stocks (see Unit I.C.2 ofthis preamble).

EPA believes that this is an appropriate category of substances under section 26(c) because they are similar inmolecular structure and inuse and because their common phosphate triester functionality confers the potential for similarbiological activity. This category is also "suitable for classification" because the ITC designated aryl phosphates as a category for priority consideration for testing.

EPA is developing a general policy under TSCA section 4(a)(1)(B) (the "B" policy) inwhich itwill articulate its criteria formaking findings under this provision. The "B" policy is being developed in response to the April 12, 1990, decision in CMA v.EPA, 899 F.2d 344 (5th Cir. 1990), in which the Court remanded the TSCA section 4 rule for

cumene toEPA to "articulate the standards or criteria on the basis of which it found the quantities ofcumene entering the environment from the facilities in question tobe 'substantial' and human exposure potentially resulting to be 'substantial."' Although
not required to do so by the cumene decision, EPA also will be articulating the criteria for 'substantial production' and 'significant human exposure.' EPA has recently published the criteria for public comment (56FR 32294).

EPAhas decided to move forward in proposing this aryl phosphate testrule under both TSCA sections 4(a)(1)(B) and (A), without waiting for notice and
comment on the generic "B" policy. The Court in CMA made it clear that EPA need not adopt a definition applicable to all cases, but may choose to proceed on

a case-by-case basis, ifit rationally explains its exercise of discretion. Thus, because this proposal articulates the criteria used in making findings under TSCA section 4(a)(1)(B) for aryl phosphate base stocks, it is not necessary to wait for publication ofa generic policy before proposing this test rule.

TSCA does not provide EPA with much guidance on what criteria and standards to use in making "B" findings. The statute does not define the terms "significant" or "substantial." The policy section ofTSCA, however, makes it clear that Congress considered testing ofchemical substances to be an important aspect ofthe Act. This section provides:

[that] adequate data shouldbe developed with respect to the effect ofchemical substances and mixtures on health and the environment and that the development of such data shouldbe the responsibility of thosewho manufacture and those who process such chemical substances and mixtures.

The legislative history ofTSCA also provides some guidance on what criteria

are to be used inmaking "B" findings. The legislative history states that "[t]he conditions specified in TSCA section 4(a)(1)(B) reflect the Committee's recognition that there are certain situations inwhich testing is desirable

even though there is an absence of information indicating that the substance or mixture may be harmful." H.R. Rept. No. 1341, 94th Cong. 2d Sess. (1976), at 18 reprinted in, A Legislative History of the Toxic Substances Control Act (Comm. Print 1976) ("Leg. Hist.") at 425, and "there are certain situations in which testing should be conducted even though there is an absence of information indicating that the substance or mixture per se may be hazardous." H.R. Conf.Rept. No. 1679, 94th Cong. 2d Sess. (1976), reprinted in, Leg. Hist. at 674. The legislative history also provides that EPA "is not limited to consideration of sheer volume of production or exposure at a specific point intime. The duration ofexposure, the level ofintensity ofexposure at various periods of time, the number of people exposed, or the extent of environmental exposure are among the considerations which may be relevant in particular circumstances." [Leg. Hist. at 425.] EPA believes that it is reasonable
to interpret the duration ofexposure and level ofintensity of exposure as relating
to "significant" human exposure, the number of people exposed ag relating to "substantial" human exposure, and the
extent ofenvironmental exposure as relating to "substantial" environmental release.

EPA recognizes thatit must not define "significant" and "substantial" in ways that would require the Administrator to make findings forevery substance in

commerce, orthe statute would have simply required testing for all substances. Nevertheless, TSCA section 4(a)(1)(B) is designed to support risk management activities under the other provisions ofTSCA. Thus, it is reasonable to interpret TSCA section 4(a)(1)(B) as authorizing EPA to require testing for every substance whose environmental or human exposure isof such magnitude ortype that it may need
to be regulated iftest data reveal adverse effects.

EPA believes that, for this category of chemical substances inwhich certain members are structurally similar, may be used interchangeably, and in which

some individual members ofthe category are produced in substantial quantities, itmay be reasonable to require testing ofa category of substances that collectively is orwill be produced in substantial quantities, greater than I million pounds per yeai and that either collectively may be released to the environment in substantial quantities, greater than 1 million pounds per year, or to which collectively there may be significant oi substantial human exposure, over 1,001, workers, 10,000 consumers or 100,000 people. Furthermore, ifEPA made findings only on individual substances that met the thresholds for substantial production, substantial release, and significant or substantial human
exposure, persons subject to the rule could avoid providing the required data by switching to substances not in
current production. Thus, EPA would have to propose another test rule every time a manufacturer switched to an aryl phosphate base stock not otherwise in production. Theoretically, the persons subject to the rule could continue switching the substances they make and
process, and EPA would never catch up. To prevent this, EPA believes it is appropriate, in this special case, to make the findings forthe category as a whole, using the same criteria for making such findings that would be used for individual chemical substances and mixtures. However, for other chemical categories EPAmay decide not to make the substantial exposure or quantities finding for the category as a whole, instead considering exposure on a subcategory or individual chemical basis.

EPA specifically solicits comment on whether EPA should use the same section 4(a)(1)(B) finding numerical thresholds for a category ofchemicals

as are used for individual chemicals, or instead require higher thresholds. When this rule is promulgated, EPA will address all comments on the proposed criteria that are relevant to this rule as well as comments on thisproposed rule. 

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## / Proposed Rules

1. EPA finds that the category ofaryl phosphate base stocks isproduced in substantial quantities. Manufacturers recently submitted production,levels of. individual category members toEPA as confidential business information. However, a nonconfidential EPAestimated aggregate category production total of 72.1 million pounds is available (Ref. 6).

EPA is reserving discussion on what it considers to be the minimum production volume that can be considered "substantial" until it promulgates its "B'" policy.Nevertheless, EPA finds that 72.1 million pounds per year clearly is above the minimum level that can be considered "substantial." EPA believes it is reasonable to interpret substantial production to mean large production, and that 72.1 million pounds is a large amount ofproduction. Although EPA does not know the exact percentage of chemical substances in commerce with production volumes above 72.1 million pounds per year, the TSCA section 8(b) inventory of the substances in

commerce shows that only 4.5 percent of the listed substances have production volumes over 10 million pounds, together accounting for over 95 percent of the total production ofall substances produced in the United States (see 56 FR 32294, 15July 1991). Moreover, the inventory shows that only about 1.5 percent ofthe listed chemical substances in commerce have production volumes over 100 million poundsperyear. Thus, EPAbelieves that substances with production volumes of at least 72.1 million pounds
per yearcomprise somewhere between 1.5 percent and 4.5 percent ofthe substances in commerce, and together
account for over95 percent ofthe total production ofall substances produced in the United States.EPA believes thatit is reasonable to conclude that this small group ofsubstances (i.e., the top 1.5 to 4.5 percent according to production volume), which account forthe vast majority ofall production, clearly are substances with substantial production.

2. EPA finds that the use ofaryl phosphate base stocks invarious products results in substantial human
exposure to these base stocks. Aryl phosphate base stock components generally comprise 0.5 to 20parts per hundred parts ofresin,or up to 45 percent by weight ofplastic forrmlations lRef. 73), and0.5 to 100 percent offunctional fluids (Ref.35) (0.5
to4 percent as antiwear additives and 100 percent ashydraulic fluids).

Exposure potential in the workplace is substantial. The 1980 National Occupational Hazard Survey (NOHS) update indicates more than 2 million workers are exposed to arylphosphate base stock components {Ref. 51). Although it is difficult to evaluate
exposure numbers in subsequent data,
e.g., NOES (Ref. 52), because of inconsistent reporting terminology (see Unit LD.2 ofthispreamble), EPA does
not know ofany reason why the number ofworkers would have changed significantly between 1980and 1991.

Exposure in the workplace occurs via inhalation and dermal contact. While
most of the aryl phosphate base stocks

are highboiling-point liquids, theymay be volatile or form aerosols in certain applications. For example, a NIOSH walk-through ofa General Motors Die Cast Department in Rochester, NY, in which aryl phosphate-containing hydraulic fluids were used at 100 *F. found TPP and IPP at concentrations of 0.57 and 0.013 mg/m 3

,respectively (Ref. 75).

EPA estimates workers having dermal
exposure to aryl phosphate base stocks may have 1300 to 3900 mg/day exposure ifno protective clothing is worn (Ref. 35). Aircraft maintenance workers frequently work with hydraulic fluids and may be at particular risk.EPA described this exposure pattern inits proposed test rule forTBP (Ref. 71). The Tributyl Phosphate Task Force, an industry group, sponsored a survey of aircraft worker exposure to tributyl phosphate, and provided estimates that 2,200 employees in tis industry are routinely exposed to aircraft hydraulic fluid and 43,000 mechanics may, at various times, be exposed (Ref. 34). EPA believes exposure estimates provided forusers of aircraft hydraulic fluids containing TBP are applicable tousers of those containing aryl phosphate base stocks, as the applications ofso&me of the arylphosphate base stocks are similar.

Some ofthese functional fluids are manufactured to meet military specifications. Responding to arecent query by EPA, the U.S. Armyresponded that there was potential TOCP exposure at 19 bases involving 196 military and 146 civilian workers (Ref.74).

In addition to worker exposure, the general population usesplastic in many forms andis potentially exposed to ryl phosphates from base stocks used as plasticizers. Thebeat in a cdosed automobile can volatilize plasticizers used in upholstery or otherplastic components, and has been shown to produce a visible film ofTCP on the inside of automobile windshields (Ref. 17). This means millions ofAmericans may be inhaling TCPin automobiles on
a regular basis, particularly onhot days. Room temperature water can leach plasticizers out ofplastics (Refs. 2and 7]. Thus,people who drink out ofplastic glasses, wash plastic items or handle
any such plastic items containing aryl phosphate plasticizers, may be exposed
to aryl phosphates through that water.

Disposal ofplastics generates additional general population exposure potential, as aryl phosphates may leach

out ofplastics in landfills and enter groundwater (Ref. 7). Thus, human populations near landfills may be exposed to aryl phosphates intheir drinking water. Incineration may cause aryl phosphates to volatilize (Ref. 7) potentially causing populations of people living near incinerators to be exposed to aryl phosphates in the air. One EPA report has postulated that as much as 80 percent ofplasticizers may volatilize or leach out (Ref. 73). General population exposure is further confirmed by the detection of aryl phosphates in human adipose tissue {Ref. 64).

EPA believes that it is reasonable to interpret the term "substantial human exposure" tomean widespread human
exposure, or in other words, exposure f

a large number ofpeople.EPA believes that exposure of 2 million workers is substantial exposure because, where millions ofworkers are exposed to a chemical substance, it is reasonable that EPA should have data n the potential hazards associated with the substance

so that EPA can implement appropriate risk management efforts where
necessary to protect workers against unreasonable risk.As ageneral matter. EPA has found that workers tend to be subject to routine orepisodic exposure

over a longperiod oftime. The Court in CMA recognized that there could be

some -verlap between substantial and significant hImanexposure. "it is not necessarily clear that 'significant' and 'substantial' as used inclause (II) must be understood in a way thatprevents their respective meanings or requires that any factor relevan to one may be necessarily irrelevant tothe other." CM0A at 350,note 17.Thus, exposure, to be considered substantial, does not have
tobe as widespread for workers as for

consumers orthe general population. EPAbeleves thatexposure of2milion workers is widespread mough to necessitate testing for thepotential hazards ofthe substances to evaluate whether worker protection efforts are necessary.

Moreover, EPA believes that millions of consumers may be exposed to aryl phosphate base stocks due to their
presence in plastics and thatmillions of members ofthe general population may be exposed tomyl phosphte base 

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stocks that leach out ofplastics in landfills and are released into the air during incineration ofplastics. EPA believes thatpotential exposure of millions ofconsumers and members of the general public to aryl phosphates is substantial exposure because where millions ofpeople are exposed to chemical substances, itis reasonable thatEPA should have data on the potential hazards associated with the substance so that EPA can implement appropriate risk management efforts where necessary to protect consumers and members ofthe general public against unreasonable risk.

3. EPA finds that aryl phosphate base stocks used in various products are released to the environment in substantial quantities. An EPA report estimated that I to 3 million pounds of aryl phosphate base stocks may enter the environment annually (Ref.42].

TPP has been detected in surface
waters from the San Francisco Bay (Ref. 39) to the Delaware River (Ref. 60). Los Angeles rainwater was found to contain TPP (Ref. 33). A 1986 survey found TPP in at least three major waterways, in both sediment and fish (Ref.72]. Substantial release is indicated by the
presence of aryl phosphates (TPP,IPP, TXP, TCP) in water (Refs. 31, 39, 41, and 60), sediment 

### (Refs. 39, 18, 31, 41, and 72) and fish (Refs. 37, 39, and 72).

IPPwas detected in soil and vegetation samples near production sites (Ref.18).

The presence ofTPP and EDP in foodstuffs (Refs. 19, 26, 27, 28, and 29) and ofTPP inhuman adipose tissue (Ref. 64) suggests the possibility of ingestion ofthese chemicals.

TPP has been found in the waterextractable fraction from items such as plastic car upholstery (Ref. 2). Disposal of such plastics through landfills or incineration adds to environmental
exposure, as leaching ofplasticizers or volatilization may occur (see Unit II.A.2 ofthis preamble].

4. Evidence for substantial production, substantial human exposure and substantiai environmental release. EPA believes that the phrase "released into the environment in substantial amounts" is intended to capture substances with extensive release to the environment, which in itselfwould be sufficient

reason to require testing in the absence ofany information that the substance may be hazardous to human health or the environment. In other words, as with substantial production, release of substantial quantities means large release. Aryl phosphate base stocks are released into the environment in quantities of 1million to3 million pounds per year. EPA finds that I million to 3 million pounds ofrelease to the environment is a sufficiently large 

### release thatEPA should require testing to determine whether measures should be taken to reduce risk to the environment. Moreover, the Toxics Release Inventory (TRI), under the Emergency Planning and Community Right-to-Know Act,42 U.S.C. section 11023, 

### shows that 37 percent ofthe listed substances have releases over I million pounds, accounting for over 99 percent ofthe total reported releases on the TRI by volume released. Because the TRI does not include all substances, less than 37 percent ofall substances would have releases above I million pounds. EPAbelieves that it is reasonable to conclude that this small group of substances (i.e., less than37 percent), which accounts for over 99 percent ofall releases, clearly are substances with substantial releases.

B.FindingsUnderTSCA Section 4(a)C1)(A)16)



### Pursuant to section 4(a)(1)(A)(i) of TSCA,EPA finds that the manufacturing, processing, use, distribution in commerce, and disposal ofaryl phosphate base stocks usedin various prcducts may present an unreasonable risk ofinjury to human health and the environment.

1.Evidenceof potential foradverse humanhealtheffects. Subchronic toxicity testing ofTPP,the most acutely toxic aryl phosphate, demonstrates effects in liver,kidney and adrenals (Ref.30). TCP demonstrates the same toxicities as TPP (liver,Refs. 30 and 54; kidney and adrenals, Refs. 54 and 59), and also affects the immune system (Ref.10). Long-term treatment with DBP damages liver,kidneys and blood (Refs. 46 and 49). Santicizer 148 (a mixture of 87 to 91 percent isodecyl diphenyl phosphate, 5to 7percent di(isodecyl] phenyl phosphate and 4 to 6 percent TPP) affects both the liver and the hematologic system (Ref.48).

Since the 1930s, various individual and combined aryl phosphates have demonstrated neurotoxicity, including phenol-type syndrome (muscular tremors, hyperexcitability, spadtic rigidity,muscular weakness and generalized flaccid paralysis, perhaps dueto degradation to the phenol or cresol) (Refs.62], as well as OPIDN, the well-known human syndrome caused by certain individual aryl phosphates (see Ref. 32). Several cases in humans, primarily due to the tricresyl phosphates, have been reported (see Ref.1). Studies performed on individual tricresyl phosphate isomers indicated the major neurotoxicant was TOCP (Refs.61 and 63). Manufacturers, therefore, reduced the TOCP content of theirproducts. However, a recently submitted TSCA section 8(e) hen study (Ref.40) indicates that complex TCPcontaining aryl phosphates containing less than 0.1 percent TOCP have neurotoxic effects similar to those arising from exposure to pure TOCP.

Three recent studies have demonstrated thereproductive toxicity ofTCP in several species and strains of laboratory animals (Refs. 12, 13 and 15). The NTP and NIEHS studies both used TCP with less than 0.1 percent TOCP, while EPA's study used TCP with less than 9percent TOCP. All three studies showed effects on male reproductive parameters, and histopathologic effects

were seen in the ovaries in the EPAsponsored study. Both the EPAsponsored and NIEHS-sponsored studies demonstrated developmental toxicity, while the NIEHS study also showed reproductive effects in the F, generation at the lowest dose.

A two-generation reproductive and fertility studyhas also been performed

on dibutyl phenyl phosphate (Ref.29a). Inthe Fo generation survivability ofpups
was decreased in both the mid-level and high dose, while in the F generation, only the high dose was so affected.

A confidential TSCA section 8(e) study was submitted toEPA in 1990 demonstrating similar reproductive effects with an additional aryl phosphate.

TOCP has been tested in a standard rat developmental toxicity study (Ref. 67), with significant increases in mean pup body weight at doses as low as 87.5 mg/kg. Further,the two-generation reproductive study on TCP in mice showed significant developmental effects in the pups, with decreases in litter size and live-born pups as well as decreased body weight (Ref.15). A onegeneration study in Long-Evans rats withTCP (Ref. 12) also indicated developmental toxicity effects: decreases in percent ofmothers delivering live-born young, and decreases in litter size and pup viability.

2.Evidenceof potential for environmentaltoxicity.Mayer et al. (1981) reported rainbow trout exposed to Pydraul 50E (arylphosphate-containing hydraulic fluid), Pydraul l!5E (aryl phosphate-containing hydraulic fluid), or either oftheirmajor aryl phosphate components, NDP and cumylphenyl diphenyl phosphate (CDP), developed
cataracts after 90 days' exposure. These complex substances also affected bone development and bone collagen content. Reduced growth and survival rates were
seen with the two mixtures and also with CDP. With Pydraul 115E, exposure 2146

### Federal Register / Vol. 57, No. 12 / Friday, January 17, 1992 / Proposed Rules

to 16 pg/L (microgram/liter) and above 

### also caused impaired swimming and feeding activities. This study also examined lake trout fed Pydraul 50E for 120 days and observed cataract effects and growth reduction at 5pjg/L, and effects on vertebral collagen at 2.6 Pg/L. Growth and survival were affected in fathead minnows exposed to Pydraul 50E for 30 days at 752 ug/L. Precursors to eye cataracts were seen histologically at 317 ,g/L. The most sensitive endpoint in this series oftests was thereduced vertebral collagen in rainbow trout following 90 days ofexposure to CDP at 0.22Pg/L (Ref. 39).



### A4-month feeding study on Pliabrac 521, an arylphosphate containing TPP. TCP, TXP and cresyl diphenyl phosphate, indicated reproductive toxicity in the minnow (Phoxinus phoxinus) (Ref.5).

A4-month exposure to IMOL S-140 (composed ofTCP,TXP, and assorted otherphosphates) in rainbow trout resulted in chronic toxicity, indicated by altered feeding behavior, increased

serum enzyme levels ofserum glutamic transaminase and lactic dehydrogenase (LDH), presence ofmuscle LDH in serum and discoloration of internal fatty tissue (Ref.36).

Ninety-day studies in the fathead minnow for several aryl phosphate base stocks showed differingresponses (Ref. 16). The authors indicated thatfor Santicizer 148 (IDP,TPP), the most sensitive endpoint was growth, while for Fyrquel GT (BDP,TPP), Phosflex 31P (TPP, IPP), and Pydraul 50E (NDP, CDP). the most sensitive endpoint was survival. Gross observation ofthe minnows did not demonstrate the cataract problems reported in1981 by Mayer et al. (Ref.39).

3. 

### Evidenceof potential for unreasonable risk.In determining that a substance may present an unreasonable risk, EPA must consider both the potential hazard ofthe substance and the potential for human and environmental exposure to the substance. EPA estimates that 2million workers and additional millions of

consumers and members ofthe general population may be exposed to aryl phosphate base stocks. In fact, EPA finds that the amount ofhuman exposure to aryl phosphate base stocks is substantial. It is notnecessary for human exposure to be "substantial" to support a finding ofpotential unreasonable risk. Nevertheless, where human substantial exposure does exist, that exposure necessarily is widespread enough to support the exposure component ofa potential risk finding. As discussed above, aryl phosphates have been shown to cause human neurotoxicity, and the potential for others such as liver, kidney, adrenal and blood effects, reproductive toxicity and developmental toxicity. The widespread human exposure coupled with the potential human hazards associated with arylphosphates indicates that aryl phosphate base stocks may present a risk to human health.

EPA estimates aryl phosphate base stocks are released into the environment in quantities of 1 million to 3million pounds per year. In fact, EPA finds that 1 million to 3 million pounds of aryl phosphate base stocks released into the environment per year constitutes substantial release into the environment. It isnot necessary for release into the environment to be "substantial" release to support a finding ofpotential unreasonable risk to the environment. Nevertheless, where substantial release into the environment exists, thatrelease necessarily islarge enough to support the exposure component ofthe potential risk finding. As discussed above, aryl phosphate base stocks have been shown to cause cataracts, reduced growth and survival rates, impaired swimming and feeding activity, reproductive toxicity, chronic toxicity, and reduced vertebral collagen in fish. The large release into the environment coupled with the potential environmental hazards associated with aryl phosphate base stocks indicates that aryl phosphate base stocks may present a risk to the environment.

From the information presented above

on the hazard potential of aryl phosphate base stocks and the amount ofpotential human and environmental exposure to arylphosphate base stocks that are used in various products, EPA finds that the manufacturing, processing,

use, distribution in commerce, and disposal of aryl phosphate base stocks
may present an unreasonable risk of injury to human health and the environment.

C.FindingsUnder TSCA Section 4(a)(1)(A)(ii)and(B)(i)

Pursuant to section 4(a)(1)(A)(ii) and (B)(ii) ofTSCA, EPA finds that, for all substances comprising the aryl phosphate base stock category, data are insufficient to determine or predict the effects ofmanufacturing, processing, distribution in commerce, oruse ofthese substances on health and on the environment.

In evaluating the testing needs for the aryl phosphate base stock category, EPA considered all available data including information in the ITC's report, TSCA section 8(d) and 8(e) data, comments received following the publication of the ANPR, and recent scientific publications. An EPA review (Ref. 66) of information available through early 1987 is available. Later sources are included in the docket for this rulemaking.

Without more complete information regarding what was actually tested, and in some cases, how the studies were performed, none ofthe studies discussed in Unit II.B ofthis preamble are acceptable toEPA for the purpose of risk assessment.

1. Subchroniceffects.Monsanto submitted a 3-month feeding study on DBP with Sprague-Dawley rats in March 1987 (Ref. 49). The study was not conducted according to EPA guidelines,

as EPA's GLPs require a detailed analysis of all components inthe tested compound. However, the report only identified the components (DBP, butyl diphenyl phosphate and TBP) and gave

no percentage composition. Analyses of
test material in food reported only the levels ofDBP.

Similarly, two other subchronic studies, one on TCP (Ref.59) and the other on Santicizer 148 (Ref.48), appear to meet the Agency's guidelines (ortheir equivalent), but inadequate test substance identification.

A subchronic study on tertbutylphenyl diphenyl phosphate (Ref. 43) may have an appropriate test protocol, but the high dose (1000 ppm in the diet) induced no treatment-related effects. EPA guidelines require that the high dose for a subchronic study induce

some significant toxicity. In lieu ofthis EPA needs evidence that an appropriate high dose level was selected. In some

cases EPA has accepted studies that use

a level that exceeds potential human
exposure by at least a factor of a hundred. These conditions have not been met for this study.

2.Neurotoxicity.Standard acute hen studies demonstrated OPIDN for TCP, TXP and IPP.Subsequently, FMC conducted a 90-day subchronic assay in the hen with Kronitex 50 (IPP) that may have been sufficient to reasonably predict or determine IPPneurotoxicity, but information on the material tested

was insufficient for EPA to evaluate the study. The study in question describes the material tested simply as C8096-126-
1 Phosphate Ester from FMC. However, FMC's cover letter stated this was Kronitex 50 (Ref. 24). The Material Safety Data Sheet (MSDS) (Ref.25) gives the composition of Kronitex 50 as phenol, isopropylated, phosphate (3-1) (Cas No. 68937-41-7). EPA has three technical listings ofthe chemical analysis ofKronitex 50 (none associated with this study): two from the manufacturer (Refs. 20 and 21) and one from the published literature (Ref. 53). 

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The three listings are significantly different. For instance, the level of triphenyl phosphate in the three papers ranges from 24.9 to33 percent. This difference may not affect the final toxicity result, but EPA is requesting
comment on this issue (Unit IV.A.1 of thispreamble).

A multi-dose study ofTOCP has been performed inEngland, but published data on the methodology do not give enough information for EPA's needs (Refs. 56 and 57).

Acute neurotoxicity results on the tert-butylphenyl phosphates are mixed. Of the 12 studies on various forms of tert-butylphenyl phosphate, 7 are negative but5 show diverse levels of OPIDN (Refs. 22, 23, 44, and 65 [two reported in Ref. 22]).

EPA does not propose repeating acute hen neurotoxicity studies for those aryl phosphate base stocks for which acceptable studies have already been completed and reviewed for the ANPR. However, DBP, one of the chemicals subject to this proposed rule, was acutely tested by Industrial Bio-Test. Tests carried outby the latter laboratory

are questionable, but ifthe results were independently and appropriately audited, and the test substance adequately defined, EPA will decide ifit is acceptable orwhether further testing is required.

3. Reproductiveeffects. A twogeneration reproductive study on TCP has been performed by NIEHS (Ref.15). This was a continuous breeding study in mice using TCP with less than 0.1 percent TOCP.Reproductive effects

were seen in both sexes, with sperm motility decreases seen in the F1 generation at the lowest dose tested. A
recent section 8(e) study (claimed as CBI) on another aryl phosphate base stock showed similar effects.

A two-generation reproductive and fertility study has also been performed

on dibutyl phenyl phosphate (Ref. 29a). This study also was done using EPA guidelines, except for lack of information on the test substance. In the Fo generation survivability ofpups was decreased in both the mid-level dose and the high dose, while in the F generation, only the high dose was so affected.

These studies may be acceptable to EPA forrisk assessment ifsubmitters

can demonstrate that the test substances used were equivalent to whatis now manufactured.

The studies on developmental toxicity submitted to EPA also lack adequate identification of test substance. Monsanto reported on studies fortwo plasticizers, Santicizer 141 and Santicizer 148 (Ref.58). The study protocols are adequate, but the 3000 mg/ kg/day high dose forthe Santicizer 148 did not cause significant maternal toxicity. EPA guidelines require that significant maternal toxicity be elicited
at the highest dose, to determine whether developmental toxicity will

occur at levels below those that are toxic to the mother. That is, ifno developmental effects are seen, then regulating the dose affecting the mother will protect the child. As with the subchronic toxicity guidelines, ifthe dose is high enough to guarantee a hundred-fold level above potential human exposure, then EPA may consider the study adequate.

Monsanto performed two additional developmental toxicity studies, on Santicizer 154 (Ref.47) and BDP (Ref. 45), but neither produced maternal toxicity.

4.Environmental effects. EPA believes acute fish toxicity information is adequate for the substances tested. Because information from the ELS testing will include acute range-finding data, EPA is not proposing acute toxicity testing foruntested arylphosphate base stocks. However, data on long-term effects are deficient, and more information is needed forrisk
assessment. Fish toxicity data discussed in Unit II.B ofthis preamble are primarily from European studies on marketed products; the test substances forwhich analytical information was provided did not appear to include any aryl phosphate base stocks presently marketed in the United States.

D.Findings UndersTSCA Sections 4(a)(1)(A)(iii) and(B)(iii)

Pursuant to section 4(a)(1)(A)(iii) and (B)(iii) ofTSCA, EPA finds that testing ofthese substances isnecessary to determine or predict the effects of manufacturing, processing, use, distribution in commerce and disposal ofall substances in the aryl phosphate base stocks category.

Under section 4(a)(1)(A)(iii) and (B)(iii), EPA finds that testing aryl phosphate base stocks is necessary to develop data for chemical analysis, organophosph. rus-induced delayed neuropathy, two-generation reproductive and fertility effects, 120- day post-hatch rainbow trout ELS effects, anaerobic biodegradation, chronic Daphnia toxicity, subchronic toxicity, aerobic biodegradation, microcosm effects, subchronic neurotoxicity and developmental toxicity. EPA believes that data resulting from this testing will be relevant to a determination as to whether manufacturing, processing, distribution in commerce, use and 

### disposal ofaryl phosphate base stocks does ordoes notpresent an unreasonable riskofinjury to health or the environment.

III. Proposed Rule

A. ProposedTestingandTestStandards

On the basis ofthe findings in Unit II ofthis preamble, EPAis proposing a test rule foraryl phosphate base stocks that meet the category definition specified in UnitL.A ofthis preamble.

Thiswould be a two-stage testrule. First, therule would require submission ofchemical analysis data obtained by GC/MS. EPA would require for firststage information any individual aryl phosphate positional isomer, except TOCP, or any other substance present in

a base stock, to be identified and quantitated ifpresent at a concentration of1 percent orgreater, quantitation for TOCP would be required to ±0.5 percent. TOCP would have to be quantitated, to ±h0.05 

### percent, unless present at less than 0.10percent. The Agency wouldnotify manufacturers by certified mail if: (1)Aparticular chemical to be tested demonstrates equivalence to another manufacturer's product and testing costs may be shared; or,(2) the chemical in question does not demonstrate equivalence to another aryl phosphate base stock and testing costs may notbe shared.

EPA would evaluate the analytical chemistry data and determine whether any base stockis equivalent to another. EPA proposes as equivalence criteria that any two base stock substances be considered equivalent ifall the individual aryl phosphate components ofthe two substances are within2 percent ofeach other,unless, for a situation involving three ormore base stocks, thisresults in a range greater than 4 percent for any component. In such a case. EPA would apply itsbest scientificjudgement.

Because ofthe economic impact of certain ofthese tests on some category members,EPA has prioritized the second-stage tests, providing three levels oftesting.Level I is the base set ofrequired testing foraryl phosphate base stocks having aggregate annual production volumes ofat least I but less than 5 million pounds: 120-day posthatch rainbow trout ELS test; three hen neurotoxicity tests

- 

### acute neurotoxic esterase (NTE), acute organophosphate delayed neuropathy, and subchronic organophosphate delayed neuropathy (lriggered by a positive NTE orpositive acute OPIDN study); and a twogeneration reproductive test. Level 2 includes additional tests required for 2148

### Federal Register / Vol. 57, No. 12 / Friday, January 17, 1992 / Proposed Rules

aryl phosphate base stocks having aggregate annual production volumes of
at least 5but less than 10 million pounds: anaerobic biodegradation; chronic Daphnia; and subchronic toxicity. Level 3 includes additional testing for aryl phosphate base stocks having aggregate annual production volumes ofat least 10 million pounds: aerobic biodegradation; microcosm; developmental toxicity; subchronic rat neurotoxicity

- functional observation battery (FOB), motor activity (MA)and neuropathology (NP). EPA would notify manufacturers when they meet trigger levels, as determined from the proposed section 8(a) production reporting. Present and future aryl phosphate base stock manufacturers would be subject to testing requirements.

Proposed Test Standards CFR citations

Level I

............................................

120-Day post-hatch trout 40 CFR 797.1600

ELS. Neurotoxicity inthe hen

...........

Acute NTE

.............................. 40 CFR 798.6450 Acute OPIDN

......................... 40 CFR 798.6540 Subchronic OPIDN, if trig- 40 CFR 798.6560

gered. Two-generation reproduction 40 CFR 798.4700

andfertility effects.
Level 2

.........................

Anaerobic biodegradation

........ 40 CFR 796.3140 Chronic Daphnia

........................ 40 CFR 797.1350 Subchronic toxicity

.................... 40 CFR 798.2650
Level 3

............................................ Aerobic biodegradation

............. 40 CFR 799.700 (Bourquin paper (Ref. 9) incorporated by reference) Microcosm ecosystem

.............. 1797.3050 (proposed) Neurotoxicity in the rat (may

be combined with subchronic per specific guideline instruction; FOB and MA acute testing required). FOB

......................................... 40 CFR 798.6050 MA

........................................... 40 CFR 798.6200 NP

........................................... 40 CFR 798.6400 Developmental toxicity

.............. 40 CFR 798.4900

The original ITC designation also recommended EPA investigate mutagenicity and oncogenicity and conduct epidemiology studies. However, considerable mutagenicity testing on aryl phosphates before and after the ANPR has been predominately negative, and EPA is not proposing such testing at this time. NTP is testing TCPfor oncogenicity, and EPA has decided to await the outcome ofthis study before deciding ifoncogenicity testing on other aryl phosphate base stocks is necessary. Any subsequent oncogenicity requirement would be the subject ofa separate rulemaking. Epidemiology is discussed in Unit IV.5 ofthis preamble.

New aryl phosphate base stocks subject toTSCA section 5would also be subject to thisrule. Section 5(b) ofTSCA requires that ifa person submits a notice
to EPA under section 5(a)(1) before the manufacture or processing ofa chemical substance, and the substance is subject
to a section 4 testrule promulgated before the submission of such notice, the data required by the section 4 test rule shall be submitted at the same time notice is submitted in accordance with section 5(a)(1). In other words, anyone making a "new" aryl phosphate base stock must first do the chemical analysis under § 799.700(e) and submit that analysis with the premanufacture notification to comply with §799.700(c)(2). New chemical manufacturers will not be required to do tiered testing, however,until EPA has evaluated the chemical analysis data and determined ifthat aryl phosphate base stock is equivalent to any other substance, and ifan aggregate production volume triggering stage 2 testing for that group ofequivalent substances has been met. If, at the time

a final test rule ispromulgated, a substance has already been submitted
to EPA and is being reviewed pursuant
to section 5(a), EPA requires that the submitter provide the data required by this testrule. Category members subject
to a section 5(e) order (i.e., already reviewed by EPA and being regulated) will be re-reviewed by EPA to determine ifdata required by the test rule are
necessary.
B. TestSubstances

All aryl phosphate base stocks, as defined by this rule, would be subject to this testrule. EPA has identified 12 aryl phosphate base stocks that are in production at this time (Ref. 55). Base stocks differing from one another by

more than 2 percent in a single component (0.1 percent for TOCP) would be considered different base stocks for purposes ofthis rule.Any other base stock meeting the definition ofaryl phosphate base stocks thatEPA is not aware ofor that comes into production in the future would also be subject to this testrule. See Unit I.C.3.d ofthis preamble for a more complete discussion ofthe background and decisions for the following substance listings.

The 12 aryl phosphate base stocks EPA believes are in production are as follows:

1. tert-Butylphenyl diphenyl phosphate (CAS No. 56803-37-3) or isobutylenated phenol, phosphate (3:1) (CAS No. 68937-40-6) (basedon a 1:3 mol ratio isobutylene to phenol).

2. bis-(tert-Butylphenyl) phenyl phosphate (CAS No. 65652-41-7)or isobutylenated phenol, phosphate (3:1) (CAS No. 68937-40-6) (based on a 2:3 mol ratio isobutylene to phenol).

3. tris-(tert-Butylphenyl) phosphate 

### (CAS No. 78-33-1) or isobutylenated phenol, phosphate (CAS No.68937-40-6) (based on a 1:1 mol ratio isobutylene to phenol).

4. Di(n-butyl) phenyl phosphate (CAS No. 2528-36-1).

5. 2-Ethylhexyl diphenyl phosphate (CAS No. 1241-94-7).

6.Isodecyl diphenyl phosphate (CAS No. 29761-21-5).

7. Isopropylphenyl diphenyl phosphate (CAS No. 2810&-99--8) or phenol, isopropylated, phosphate (3:1) (CAS No. 68937-41-7) (based on a 1:3 mol ratio propylene to phenol).

8. bis-(Isopropylphenyl) phenyl phosphate [CAS No. 28109-00-4) or phenol, isopropylated, phosphate (3:1) (CAS No. 68937-41-7) (based on a 2:3 mol ratio propylene to phenol).

9. tris-(Isopropylphenyl) phosphate or phenol, isopropylated, phosphate (3:1) (CAS No. 68937-41-7) (based on a 1:1 mol ratio propylene tophenol).

10. Tricresyl phosphate (CAS No. 1330-78-5), or tar acids, cresylic, phenyl phosphate (CAS No. 68952-35-2).

11. Triphenyl phosphate (CAS No. 

### 115-86--6).

12. Trixylyl phosphate (CAS No. 25155-23-1) or tar acids, cresylic, C-8 rich, phenyl phosphate (CAS No. 68952- 33-6).

For this proposed rule, EPA would not require testing ofpure chemicals, but rather the base stocks to which persons (manufacturing workers, users, consumers, general populace, etc.), or the environment are actually exposed. EPA would require chemical analysis as the first stage oftesting to help define equivalence for category members.

Any substance meeting the aryl phosphate base stock category definition, even ifnot named inthe final rule, would be considered a member of this category and subject to this test rule.

C Persons Requiredto Test

Because ofthe findings inUnit II of this preamble, EPAis proposing that
persons who manufacture (including
persons who import) or process or intend to manufacture and/or process

an aryl phosphate base stock as defined by this rule, at any time from the effective date ofthe final test rule to the end ofthe reimbursement period, be subject to the testing requirements 

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contained in this proposed rule.This period is defined in 40 CFR 791.3(h).

Each manufacturer of a specific aryl phosphate base stock would pay a pro rata share ofthe aggregate cost of testing that specific test substance In proportion to itsmarket share. Manufacturers (including importers) potentially subject to this rule should consult theprocedures in 40 CFRpart 790.As explained in40 CFR part790, initially manufacturers, but not processors, ofone or more ofthese substances would berequired to submit letters ofintent or exemption applications. Pursuant to a recent amendment to part 790,small quantity research and development manufacturers are not required to submit letters ofintent or exemption applications. Such manufacturers should consult the Federal Register at 55FR 10881, May 7, 1990, forfurther details.

Product compositions may change because offeedstock orprocessing changes, and the toxicity ofindividual aryl phosphate components can vary widely.For this reason, chemical analysis data are needed to define the test substance and to prove equivalence ofproducts ifthere are two ormore manufacturers. As new manufacturers

move into the market, they would also have to demonstrate equivalence, or conduct testing.The Stage I chemical analysis would be required foreach inproduction aryl phosphate base stock in this category.

D.ReportingRequirements
As required under40 CFR 799.10, EPA is proposing thatall data developed under this rulemust be reported in accordance with its GLP standards which appear in 40 CFR part 792.

As required by TSCA section 4(b)(1)(c), EPA is proposing specific reporting requirements for each ofthe proposed test standards as follows: Final reports for the first stage of this

testrule, the chemical analysis data, would be due no laterthan 6 months after the date ofpublication of the final rule.

Final reports for second stage studies would be due atIntervals specified below following the notification of manufacturers by EPAby certified mail that the second stage oftesting should begin on their substance or that production volume had triggered another level oftesting.

Proposed Test Standards

Level

............. ...................................... ................................................................................................ 120-Day post-hWAt troutELS

....... ............. . .......................... ........... . .................................... Neurotoxicity in the hen

................. Acute NTE

............................ AcuteOPIDN

........................ Subchronic OPIDN............. Two-generation reproduction and

Anaerobic bodegdatlon

.............................................................................. Chronic Daohna

................ .............. . .. ........ ................... .......................... ......... . ...... .. Subchronic toxicity

......................................................................... Level 3

. .... .. .... . ....... . .............. .... ....

......................................................................................... Aerobic biodegradation

........................ .......................................................................................... M

icrocosm ecosystem

......................................................................................................................... Neurotoxicity inthe rat (may be 'combined with subchronic per spectlicguldeline instruction;

FOB and MA acute testing required).

FOB

......................................................... ....... .............................................................................. MA
......................................................................................................................................................... NP

................ i........i........................................................................................................................... Developm ental toxdcily

........... ........ ....... .............. ................................................................................... Reporting Requirements

18 months

6 months 6 months 18 months

24 months

12 months
12 months
18 months

12 months
24 months

18 months 18 months 18 months
12 months

Progress reports on these tests would have to be submitted toEPA every 6 months, beginning 6 months afterEPA notifies the manufacturers testing must proceed, until the final report is submitted.

TSCA section 14(b) governs EPA's disclosure ofall test data submitted pursuant to section 4 ofTSCA. Upon receipt ofdata required by this rule, EPA will publish a notice ofreceipt in the Federal Register as required by section 4(d) ofTSCA.

IV. Issues for Comment

A. IssuesRelatingto ChoiceofTest Substances

1. EPArequests comments on EPA's approach to choosing test substances.

Most aryl phosphate toxicity testing has been performed on multicomponent technical grade substances. EPA considered requiring testing of individual components because the literature has documented differences in toxicity between components and between individual isomers, but rejected this approach as impractical and too expensive. Instead EPA is proposing to require testing ofaryl phosphate base stocks. These may vary significantly from manufacturer to manufacturer and perhaps between batches. EPA is proposing that base stocks differing from one another by more than 2percent in a single component (0.1percent for TOCP) be considered different base stocks for purposes ofthis rule.Would this result in an unnecessary or burdensome amount ofbase stock testing? Are there better ways ormore appropriate criteria to define and differentiate base stocks? 2.How should the specific test substances be chosen?

EPA is proposing the first stage ofthis two-stage rule to enable the Agency to

assess the identity and proportions of constituents of individually manufactured aryl phosphate base stocks. EPA is addressing this issue up front rather than through the exemption application process. To assure equitable sharing ofsecond-stage testing responsibilities and costs among manufacturers in cases where multiple manufacturers produce aryl phosphate base stocksjudged by EPA to be equivalent, the Agency would have three alternative courses ofaction, as follows:

- To have EPA or the manufacturers choose one ofequivalent substances for testing. 

### ................... ............................. . ................... ....

............... .........

...................................................................................................

.............. ............................... ....... ......

. ........... .......

fer" effectB

......................... . . .... 

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### Federal Register / Vol. 57, No. 12 / Friday, January 17, 1992 / Proposed Rides

- To require testing ofa composite mixture ofequivalent aryl phosphate 

### base stocks.

- To define a "standard" test substance for each group ofequivalent substances.

EPA is proposing in this Notice that EPA will choose one ofthe equivalent substances fortesting, but desires comment on this.

3. What level ofquantitation should EPA require in the chemical analysis? Should there be a requirement to quantitate any chemical component other than TOCP ofan aryl phosphate base stock more precisely than ±2.0 percent?

Except for TOCP, the rule would require chemical analysis with identification of all components ofthe manufacturers' products present at a level of1.0 percent or greater. However, data reported in Ref.40 suggest that observed neurotoxicity fromTCP may be due toTOCP present at less than 0.1 percent.Thus,the Agency is proposing to require quantification for TOCP ifits concentration is 0.10percent or greater. For comparison, the Office ofPesticide Programs (OPP)requires identification ofall chemicals present in the test material at or above 1.0 percent concentration.

4. How detailed should EPA make the chemical analysis requirement, and what are the mostuseful techniques? Should EPA allow each submitter to supply justification forthe methods he chooses, orrequire a specific method?

EPA is proposing to require forthe chemical analysis GC/MS,which may be thebest method for conducting chemical analyses for these compounds,

as all these arylphosphate base stock components are sufficiently volatile. However, isomers in products such as TCP andTXP are difficult to separate

even on capillary columns. Determination ofspecific components such as TOCP, and analysis ofphenolic moieties by gas-liquid chromatography following alkaline hydrolysis of the phosphate estershas been proposed (Ref.50). Alternatives to GC include:

- Gel permeation chromatography.

. High performance liquid chromatography.

•Supercritical fluid chromatography. Alternatives toMS (which may be too destructive ofthe separated particles for good analysis) include: "

Nuclear magnetic resonance.

•Infrared radiation. "Ion track detector. Should any ofthese methods be considered as alternatives, particularly if theproposed method may cause destruction ofthe sample? 5. Does the exposure information on aryl phosphates support testing for all identified base stocks? Could results of

more limited testing be used as a screen to develop whether or not it is necessary to test additional base stocks?

B.IssuesRelatedto RequiredTesting

1. Should EPApropose another level thatwould have no production trigger and would include only the hen subchronic neurotoxicity and a onegeneration reproductive toxicity test for those chemicals where economic impact is severe?

According to information received by EPA. some of the aryl phosphate base stocks do not have an aggregate production level that EPA has determined will adequately support the required Level Itesting costs. The tests proposed in Level I are based on known toxicity forthe category, and, In some instances, on toxicity ofcertain components of the base stocks.

2. Should EPA require developmental neurotoxicity testing ofaryl phosphate base stocks?

EPA is requiring both hen (acute delayed neurotoxicity and NTE, and subchronic delayed neurotoxicity, if triggered) and rat (FOB, MA, NP) neurotoxicity studies, but is not proposing to require developmental neurotoxicity testing at this time. EPA's Science Advisory Panel recommended that one criterion for requiring the developmental neurotoxicity screen be "*** test substances that produce neuropathology in developing or adult animals." and another criterion be "' strong structure-activity relationships with known neurotoxicants" (Ref. 70). Should EPA propose a developmental neurotoxicity testrequirement in a subsequent rulemaking ifneurotoxicity
test results in the rat are positive?

3. Should EPA again consider Investigating whether some form of epidemiological study is indicated?

EPA did not suggest epidemiological neurotoxicity studies in the ANPR because available information suggested that a valid cohort was too difficult to identify. However, the Agency is interested in determining ifa valid cohort may now be identified. Epidemiological studies ofneurotoxic and/or reproductive effects may be warranted because ofthe suggestive

new toxicity data in these areas.

4. Should EPA require that the rainbow trout ELS test be expanded to include histopathological examination specifically for cataracts, bone development and bonercollagen deficits

as seen in Ref. 39, orcarried for a longer post-hatch period, e.g., 6 months, to 

### better ensure that anysuch effects will be observed?

EPAis proposing toextend the usual 90 day post-hatch duration ofthe ELS test in the trout to 120 days post-hatch

as a surrogate for a chronic fish test, for which EPAhas no guideline. Cataracts and reduced vertebral collagen were
seen in long-term studies ofat least 3to 4 months in trout,but not detected in a 30-day study inminnows, although histological precursors were detected (Ref.39).

5.ShouldEPA require additional testing for the aryl phosphate base stocks to address memory and other neurobehavioral deficits ifbrain and blood acetylcholinesterase inhibition is significant?

Theproposed subchronic toxicity test would include tests forblood and brain acetyicholinesterase (AChE) inhibition. References cited in the 1971 ACGIH Documentation ofthe Threshold Limit Values reported significant decreases in plasma cholinesterase in workers exposed toTOCP and ofred blood cell cholinesterase in workers exposed to TPP, even though the authors foundno other effects (Ref.4). Of more concern, a recent study on an organophosphate pesticide, diisopropylfluorophosphate, showed significant effects on short- and long-term memory, impaired matching accuracy and lengthened response times at levels at which the only other effect observed was depressed brain AChE (Ref. 11). and only after extended treatment with the chemical.

6.Is there a CBI problemifEPA informs all manufacturers ofa given base stock substance that there are othermanufacturers of thesame substance and who those manufacturers
are, and that an aggregate production volume trigger was met for that substance?

7. EPA is aware ofthe interchangeability ofsome aryl phosphates for the same end use. To gain a greater understanding ofthis factor which plays a role in the evaluations ofthe economic impact of this proposed rule, EPAis requesting the submission ofadditional data relating to interchangeability.
C. OtherIssues

1.Should EPA require reporting of exposure and release information beyond that proposed in the testrule?

EPA isproposing TSCA section 8(a) PAIR reporting for manufacturers of the aryl phosphate base stocks to enable EPA tomake better decisions on which base stocks can support the testing. Preliminary information indicates that a great deal ofhuman exposure and I I II I II I 

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environmental release results from processing and use ofproducts containing aryl phosphate base stocks, suggesting that EPA may miss important information by not requiring processors to report.

2. EPA has defined three productionlevel triggers, one at Imillion pounds for potential unreasonable risk findings, one at 5 million pounds and one at 10 million pounds for additional testing.EPA solicits comment on whether these triggers comport with manufacturers' ability to pay for the level oftesting. Is it appropriate to use these triggers based

on a high production/high exposure concern? Ifan exposure value should be included, what should it be and how could EPA apply it as a triggering mechanism?

V. Economic Analysis ofProposed Rule

EPAhas prepared an economic analysis ofthis proposed rule (Ref.6). The analysis estimates the costs of conducting the proposed testing for each ofthe chemicals, including both laboratory and administrative costs, and evaluates the potential for economic impacts as a result ofthese test costs, using a comparison between a chemical's annualized test costs and its annual revenues.

The estimated total cost ofthe maximum possible testing for each chemical is$1,076,988 to $1,656,638.

In order to evaluate the potential economic impacts of the proposed testing, test costs are annualized and compared with annual revenues from the chemicals. The annualized test costs, using a 7 percent cost ofcapital over a period of15years are $53,974 to $81,167 forLevel 1; for Levels 1 and 2, the costs

are $86,681to $99,516; for all 3 Levels, the costs are $118,247 to $181,890. The
costs ofchemical analysis were not estimated because no protocols were identified for this test.Therefore these
costs may be underestimated.

The comparison between annual costs and revenues suggests that for four chemicals, the maximum test cost may have no significant adverse economic impacts. For the remaining chemicals, the test costs do appear to pose some potential for adverse economic impacts. Please refer to the economic analysis contained in the public record forthis rulemaking for more details on testcost estimations and the evaluation of economic impacts. EPA's proposed festing and standards devised to reduce the impact oftesting costs isdescribed in Unit III.A ofthis preamble ofthis notice. VI. Availability ofTest Facilities and Personnel

EPAhas determined that test facilities and personnel are available to perform the testing specified in this proposed rule. (Ref. 8).

VII. Public Meeting

If requests for oral comments are submitted, as indicated in the dates section, EPA will hold a public meeting after the close of the public comment period inWashington, DC. Persons wishing to present comments or attend the meeting should call Mary Louise Hewlett, (202) 260-8162. The meetings

are open to the public, but active participation will be limited to those who requested to comment and EPA representatives. Participants are requested to submit copies oftheir
statements by the meeting date. These
statements and a transcript ofthe meeting will become part ofEPA's record forrulemaking.

VIII. Comments Containing Confidential Business Information

All comments will be placed in the public file unless they are clearly labeled as Confidential Business Information (CBI) when the comments

are submitted.

While a part ofthe record, CBI
comments will be treated in accordance with40 CFR part 2. A sanitized version ofall CBI comments should be submitted toEPA for the public file.

It is the responsibility ofthe
commenter to comply with 40 CFR part 2 in order that all materials claimed as confidential may beproperly protected. This includes, butis not limited to, clearly indicating on the face ofthe
comment (as well as on any associated correspondence) that CBI is included, and marking "CONFIDENTIAL", "TSCA CBI" or similar designation on the face ofeach document or attachment in the
comment that contains CBI. Should information be put into the public file because offailure to clearly designate its confidential status on the face of the comment, EPA will presume any such information that has been in the public file formore than 30 days to be in the public domain.

IX. Rulemaking Record

EPA has established a record for this rulemaking, (docketnumber OPPTS42038A). This record contains the basic information considered by the Agency in developing this proposal and appropriate Federal Register notices.

This record includes the following information: A. Supportingdocumentation (1)Federal Register notices pertaining
to this rule consisting of:

(a)Notice containing the ITC designation ofthe chemical category of aryl phosphates to the Priority List (43 FR 16684, April 19, 1978).

(b) Rule requiring TSCA section 8(a) reporting on the chemical category of aryl phosphates (47 FR 26992, June 22, 1982).

(c) Rule requiring TSCA section 8(d) reporting on the chemical category of aryl phosphates (47FR 38780, September 2, 1982).

(d) TSCA test guidelines cited as proposed test standards forthis rule, 40 CFR parts 796, 797, and 798.

(e) Notice offinal rule on EPA's TSCA Good Laboratory Practice Standards (54 FR 34034, August 17, 1989).

(f0 Notice ofinterim final rule on single-phase testrule development and exemption procedures (50FR 20652, May 17, 1985).

(g) Notice offinal rule on data reimbursement policy and procedures (48 FR 31786, July 11, 1983).

(h) Advance notice of proposed rulemaking for aryl phosphates (48FR 57452, December 29, 1983).

(i) Notice ofInventory Update Rule (51 FR 21447, June 12, 1986).

0) Notice ofAgency's first and second proposed test rules (45 FR 48510, July 18, 1980 and 46 FR 30300, June 5, 1981).

(2) Communications before proposal consisting of:

(a) Written public comments and letters.

(b) Contact reports oftelephone conversations.

B. References

(1)Abou-Donia, M.B. and D.M. Lapadula. Mechanisms oforganophosphorus esterinduced delayed neurotoxicity.Annual Review ofPharmacology andToxicology 30:405-440 (1990).

(2)Ahrens,V.D., Henion.J.D., Maylin, G.A., Leibowitz, L, St. John, LE., Jr., and D.J. Lisk. A water-extractable toxic compound invinyl upholstery fabric.Bulletin of Environmental Contamination andToxicology20:418-422 (1978).

(2a) American Chemical Society Committee

on Environmental Improvement. Guidelines for data acquisition and data quality evaluation in environmental chemistry. AnalyticalChemistry52:2242-2249 (1980).

(3)American Conference ofGovernmental Industrial Hygienists. TLVs: Threshold limit values andbiological exposure indices for 1986-1987. American Conference of Governmental Industrial Hygienists, Cincinnati, OH (1986).

(4)

American Conference ofGovernmental Industrial Hygienists. Documentation ofthe threshold limit values for substances in workroom air.American Conference of 

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### Federal Register / Vol. 57, No. 12 / Friday, January 17, 1992 / Proposed Rules

Governmental Industrial Hygienists. Cincinnati. OH (1974).

(5) Bengtsson, B.E., Tarkpea, M., Sletten, T., Carlberg, G.E., Kringstad, A. and L. Renberg. Bioaccumulatlon and effects ofsome technical triaryl phosphate products in fish and Nitocraspinipes.Environmental ToxicologyandChemistry,5:853-.1 (1986).

(6)Blake-Hedges, L Economic analysis of proposed test rule for twelve aryl phosphates (non-CBI version). CBIversion DCN 20911000422. Regulatory Impacts Branch, Office ofPollution Prevention and Toxics (OPPT), United States Environmental Protection Agency (USEPA) (April 26, 1991).

(7) Boethling, R.S. and J.C. Cooper. Environmental fate and effects oftriaryl and tri-alkyl/arylphosphate esters.Residue Reviews 94:49-99 (1985).

(8) Booz, Allen &Hamilton Inc. EPA census of the toxicological testing industry (draft report). EPA Contract 68D8-0111 for Office of Policy Analysis for the Office ofPollution Prevention and Toxics, USEPA (June 1990).

(9)Bourquin. A.W., Hood.M.A. and R.L. Games.An artificial ecosystem for determining effects and fate of toxicants in a salt-marsh environment. Development in Industrial Microbiology18:185-191 (1977). (10)Brinkerhoff, C.R., Sharma, R.P., and D.R. Bourcier. The effects oftri-ortho-tolyl phosphate (totp) onthe immune system of mice. EcotoxicologyandEnvironmental Safety. 5:368-376 (1981).

(11) Bushnell, P.1., Padilla, S.S., Ward, T, Pope, C.N. and V.B. Olszyk. Behavioral and neurochemical changes inrats dosed repeatedly with diisopropylfluorophosphate. Journal ofPharmacology andExperimental Therapeutics. 25&741-750 (1991).

(12) Carlton, B.D., Basaran, A.H., Mezza, LE. and M.K. Smith. Examination ofthe reproductive effects oftricresyl phosphate administered to Long-Evans rats. Toxicology. 46.321-328 (1987).

(13) Carlton, B.D., Irwin, R., Hejtmancik, M., Deskin.R., Ryan, M. and A.C. Peters. Reproductive toxicity oftricresyl phosphate inmale rats &mice by two dosing routes. Toxicologist.&292 (1986).

(14) Carpenter, H.M., Jenden. D.J.. Shulman, R. and J.R. Turman. Toxicology ofa triaryl phosphate oil. Archivesof Industrial Health, 20:234-252 (1969).

(15) Chapin, R.E., George, J.D.. and J.C. Lamb, IV. Reproductive toxicity oftricresyl phosphate in a continuous breeding protocol in Swiss (CD-1) mice. Fundamental and Applied Toxicology. 10:344-354 (1988).

(16) Cleveland.L, Mayer, F.L., Buckler, D.R.. and D.U. Palawaski. Toxicity of five alkyl-aryl phosphate ester chemicals to four species offreshwater fish. Environmental ToxicologyandChemistry.5:273-282 (1986).

(17) Crockett A.B. Preliminary report on aryl phosphate monitoring with attachment. Memorandum from A.B. Crockett, Environmental Monitoring and Support Laboratory, Office ofResearch and Development (ORD), Las Vegas, NV to M.P. Halper, OPPT, USEPA (1978).

(18) Crockett. A.B. Analysis ofaryl phosphate samples. Memorandum from Environmental Monitoring and Support Laboratory, ORD, Las Vegas, NV to Pat Hilgard, OPPT, USEPA (March6, 1979). (19) Daft, J.L Identification ofaryl/alkyl phosphate residues in foods. Bulletinof Environmental Contamination and Toxicology.29:221-227 (1982).

(20) FMC Corporation. Gas chromatographic-mass spectral assay of Kronitex isopropylphenyl phosphates. Technical report No. CGP-75-10. Princeton, NJ. (1975).

(21) FMC Corporation. Kronitex 50

- Mutagenicity test screening testSalmonella microsomal assay (Ames test). Princeton, NJ (1977).

(22) FMC Corporation. Neurotoxicity study in hens on commercially available phosphate
ester products. TSCA section 8(d) submission 878210588 (1977).

(23) FMC Corporation. Neurotoxicity study in hens on commercially available phosphate ester products. TSCA section 8(d) submission 878210587 (1977).

(24) FMC Corporation. Cover letter and unpublished study, the subchronic (90 day) neurotoxicity of C8096-126-1 phosphate ester
to thedomestic hen. TSCA section 8(d) submission 878214930 (1988).

(25) FMC Corporation. Kronitex (R) 50, Material safety data sheet (1988).

(26) Gartrell, M.J., Craun, I.C., Podrebarac, D.S. and E.L Gunderson. Pesticides, selected elements, and other chemicals in infant and toddler total diet samples,October, 1979- September, 1980.JournaloftheAssociation ofOfficial AnalyticalChemists. 8:1183-1183 (1985).

(27) Gartrell, M.J.. Craun, J.C., Podrebarac, D.S. and E.L Gunderson. Pesticides, selected elements, and other chemicals in adult total diet samples, October, 1979-September, 1980. JournaloftheAssociationofOfficial AnalyticalChemists.68:1184-1197 (1985).

(28) Gartrell, M.J., Craun, J.C., Podrebarac, D.S. and E.L. Gunderson. Pesticides, selected elements, and other chemicals in infant and toddler total diet samples. October, 1980- March, 1982.JournaloftheAssociationof Official Analytical Chemists.69:123-145 (1986).

(29) Gartrell, M.J., Craun, J.C., Podrebarac. D.S. and EL. Gunderson. Pesticides, selected elements, and other chemicals in adult total diet samples, October, 1980-March, 1982. Journal oftheAssociationofOfficial AnalyticalChemists.69:146-161 (1986).

(29a) Healy, C.E., Nair, R.S., Lemen, J.K., and F.R. Joharmsen. Subchronic and reproduction studies with dibutyl phenyl phosphate in Sprague-Dawley rats. Fundamental and Applied Toxicology. 16:117-127 (1991).

(30) Hierholzer, K., Noetzel, H. and L Schmidt.Comparative toxicological investigation oftriphenyl phosphate and tricresyl phosphate.Amneimittel-Forschung. 7:585-588 (1957).

(31) Jadlocki. J.F. The environmental fate and effects ofaryl phosphates and phenolics in wastewaters from theproduction of Kronitex phosphate esters. FMC, Industrial Chemicals Division. Princeton. NJ (1980).

(32) Johnson, M.K. Organophosphorus
esters causing delayed neurotoxic effects. Archives ofToxicology.34.259-288 (1975).

(33) Kawamura, K.and I.R.Kaplan. Organic compounds in the rainwater ofLos Angeles, EnvironmentalScienceand Technology.17.497-501 (1983). (34) Kneiss,J.Letter from Managing Director ofthe Tributyl Phosphate Task Force
toM. McCommas, OPPT, USEPA (July 11, 1988).

(35) Lambrecht, L. Summary engineering report.Test rule exposure assessment aryl phosphates. Chemical Engineering Branch, Economic and Technology Division, Office of Pollution Prevention and Toxics. USEPA (August 14, 1989).

(36)Lockhart, W.L., Wagemann, R., Clayton,J.W., Graham, B. and D. Murray. Chronic toxicity ofa synthetic tri-aryl phosphate oil to fish.Environmental PhysiologyandBiochemistry5:361-309 (1975).

(37) Lombardo, P. and I.j. Egry. Identification and gas-liquid chromatographic determination ofaryl phosphate residues in environmental samples.Journal ofthe AssociationofOfficialAnalyticalChemists. 62:47-51 (1979).

(36)Mathtech. Aryl phosphates market profile (non-CBI version) (July 14,1986).

(39) Mayer, F.L., Adams, W.I., Finley, M.T.. Michael, P.R., Mehrle, P.M. and V.W. Saeger. Phosphate ester hydraulic fluids: an aquatic environmental assessment ofPydrauls 50E and 115E.AquaticToxicologyandHazard Assessment:FourthConference,ASTM STP 737, D.R. Branson and K.L. Dickson, Eds., American Society for Testing and Materials,
pp. 103-123 (1981).

(40) McCullough, J.P. TSCA section 8(e) notification on tricresyl phosphate (TCP) Cas Registry number 1330-78-5. 8EHQ0788-0744S. Mobil Research and Development Corporation (July21,1988).

(41) Michael, P.R. and W.I. Adams. Final report ofthe 1982 industry-EPA phosphate esteraquatic surveillance program. Monsanto (1982).

(42) Midwest Research Institute (MRI). Assessment ofthe need for limitation on triaryl and trialkyl/aryl phosphates. EPA Contract No. 68-01-4313 (May 15, 1979).

(43) Monsanto Company. 90-Day subacute oral toxicity study with BPDP (tertbutylphenyl diphenyl phosphate) in albino
rats (1974).

(44) Monsanto Company. Neurotoxicity study with Santicizer XP 728, Lot No. MIC 248788 in chickens with package ofmaterials relating to validation ofIndustrial Bio Test Laboratories Report TSCA section 8(d) submission 878211875 (1975).

(45)Monsanto Company. Teratology study in rats (IRD-77252). International Research and Development Corporation (1979).

(46) Monsanto Company. Ninety day feeding study in rats.TSCA section 8(d) submission 878211005 (1980).

(47) Monsanto Company. Teratology study in rats with test article Santicizer 154 with cover.letter dated August 7, 1981. International Research and Development Corporation (1981).

(48) Monsanto Company. Subchronic study ofSanticizer 148 plasticizer administered in the diet to albinorats. TSCA section 8(d) submission 868600001 (1986).

(49)Monsanto Company, Three month feedin study with dibutylphenyl phosphate with Sprague-Dawley rats. TSCA section 8(d) submission 86870000222 (1980). I 

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### 1992 / Proposed Rules

(50)Muir, D.C.G. Phosphate esters. The HandbookofEnvironmentalChemistry,Vol. 3, Part C. 0. Huntzinger, ed., pp. 41-46 (1984).

(51) National Institute for Occupational Health and Safety (NIOSH). National Occupational Hazard Survey (NOHS) (1977, updated August 6, 1980).

(52) NIOSH. Unpublished provisional data ofthe National Occupational Exposure Survey (1981-83). Cincinnati, Ohio: U.S. Department ofHealth and Human Services, NIOSH (July 1, 1990).

(53) Nobile, E.R., Page, S.W. and P. Lombardo. Characterization offour commercial flame retardant aryl phosphates. Bulletinof EnvironmentalContaminant Toxicology.25:755-761 (1980).

(54) Oishi,I., Oishi, S. and K. Hiraga. Toxicity of several phosphoric acid esters in
rats. ToxicologyLetters. 13:29-34 (1982).

(55) Podall, H.E.Memorandum "Arylphosphates Associated with Specific Uses" (sanitized version), with corrections. Industrial Chemistry Branch, Office of Pollution Prevention and Toxics, to Carol Glasgow, Test Rules Development Branch, OPPT, USEPA (April 6, 1990 and April 9, 1991).

(56) Prentice, D.E. and S.K. Majeed. A subchronic study (90 day) using multiple dose-levels of tri-ortho-cresyl phosphate (TOCP): Some neuropathological observations inthe domestic hen. NeuroToxicology.4:277-282 (1983).

(57) Roberts, N.L., Fairley, C. and C. Phillips. Screening, acute delayed and subchronic neurotoxicity studies in the lien: Measurements and evaluations ofclinical signs following administration ofTOCP. NeuroToxicology.4:263-270 (1983).

(58) Robinson, E.C., Hammond, B.G., Johannsen. F.R., Levinskas, G.J. and D.E. Rodwell. Teratogenicity studies ofalkylaryl phosphate ester plasticizers in rats. Fundamentaland Applied Toxicology.7:138- 143 (1986).

(59) Saito, C., Kato, T., Taniguchi, H., Fujita, T., Wads, H. and Y. Mori. Tests ofthe subacute toxicity oftricresylphosphate (TCP) inrats. aye Yakuri 8:107-118 (1974).

(60) Sheldon, L.S. and R.A. Hites. Organic compounds in the Delaware river. EnvironmentalScienceandTechnology. 12:1188-1194 (1978).

(61) Smith, M.I., Engel, E.W. and E.F. Stohlman. Further studies on the pharmacolngy ofcertain phenol esters with special reference to the relation ofchemical constitution and physiologic action.NIH Bulletin.160:1-53 (1932).

(621 Smith, M.I., Elvove, E., and W.H. Frazier. The pharmacological action of certain phenol esters, with special reference
to the etiology of so-called ginger paralysis. USPublicHealthReport.45:2509-24 (1930).

(63) Smith, M.I., Elvove, E., Valer, P.J., Frazier, W.H, and G.E. Mallory. Pharmacological and chemical studies ofthe

cause ofso-called ginger paralysis. US Public HealthReport.45:1703-16 (1930).

(64) Stanley, .S. Broad scan analysis ofthe FY82 national human adipose tissue survey specimens. Volume III Semivolatile organic compounds. EPA-560/5-86-037, pp, 84-85 (December 1986). (65) Stauffer Chemical Company. Acute delayed neurotoxicity study with Phosflex 51B in adult hens (T-6681) (1980).

(66) Syracuse Research Corporation. Technical support document for aryl phosphates. SRC TR-88-028 (January 29, 1988).

(67) Tocco, D.R., Randall, J.L., York, R.G. and M.K. Smith. Evaluation ofthe teratogenic effects oftri-ortho-cresyl phosphate in the Long-Evans hooded rat. Fundamental and Applied Toxicology.8:291-297 (1987).

(68) USEPA. Report ofa TSCA GLP compliance laboratory inspection and data audit. Office ofCompliance Monitoring (March4-6, 1985).

(69) USEPA. Chemical update system. Confidential retrieval ofreporting information ofaryl phosphates from 1985: DCN 20-901000040 (October 11, 1989).

(70) USEPA. Federal Insecticide, Fungicide, and Rodenticide Act Scientific Advisory Panel Subpanel: A set ofscientific issues being considered by the Agency concerning neurotoxicity testing under FIFRA (October 16, 1987).

(71) USEPA. Tributyl phosphate; proposed
testrule. 52 FR 43346 (November 12, 1987).

(72) USEPA. STORET, Triphenyl phosphate. Data retiieved (October 24, 1990).

(73) Versar. Untitled draft report on aryl phosphates. Washington, DC: Office of Pollution Prevention and Toxics, USEPA, Contract 6801-5791 (1980).

(74) Walker, L.D., Deputy Assistant Secretary oftheArmy (Environment, Safety and Occupational Health, letter to M. Dominiak, Chemical Control Division, Office ofPollution Prevention and Toxics, Environmental Protection Agency (September 5,199).

(75) Zumwalde, R.D. and C. Cottrill. Industrial hygiene walk-through survey report

on organophosphorus exposures at Rochester Products Division, General Motors Corporation, 1000 Lexington Avenue, Rochester, New York. Cincinnati, OH: U.S. Department ofHealth and Human Services, NIOSH (1980).

X. OtherRegulatory Requirements

A. Executive Order12291

Under Executive Order 12291, EPA

must judge whether a rule is "major" and therefore subject to the requirement of a Regulatory ImpactAnalysis. EPA has determined that this test rule would

not be major because it does not meet
any of the criteria set forth in section 1(b) ofthe Order, i.e., it would not have

an annual effect on the economy of at least$100 million, would not cause a major increase in prices, and would not have a significant adverse effect on competition or the ability ofU.S. 

### enterprises to compete with foreign enterprises.

This proposed regulation was submitted to the Office ofManagement and Budget (OMB) for review as required by Executive Order 12291. Any written comments from OMB to EPA, and any EPA response to those comments, are included in this record. B.RegulatoryFlexibility Act

Under the Regulatory Flexibility Act (15U.S.C. 601 et seq., Pub.L. 96-354, September 19, 1980]. EPA is certifying that this test rule, ifpromulgated, would
not have a significant impact on a substantial number of small businesses because: (1)There are only a small number ofknown small manufacturers, (2] any small processors are not expected to perform testing themselves

or to participate in the organization of the testing effort, (3] they will experience only very minor cost in securing exemption from testing requirements, and (4) they are unlikely

to be affected by reimbursement requirements.

C.Paperwork ReductionAct

OMB has approved the information collection requirements contained in this proposed rule under the provisions of the Paperwork Reduction Act of 1980,44 U.S.C. 3501 et seq., and has assigned OMB control number 2070-0033.

Public reporting burden forthis collection ofinformation is estimated to average 14,174 hours per response, including time for reviewing instructions, searching existing data

sources, gathering and maintaining the data needed, and completing and reviewing the collection ofinformation. The total public reporting burden is estimated to be 170,088 hours for all.

Send comments regarding the burden estimates for any other aspect ofthis collection ofinformation, including suggestions for reducing this burden, to Chief, Information Policy Branch, PM223, U.S. Environmental Protection Agency, 401 M St., SW., Washington DC 20460; and to the Office ofManagement and Budget, Paperwork Reduction Project (2070-0033), Washington, DC 20503. The final rule will respond to any OMB or public comments on the information collection requirements contained in this proposal.

List ofSubjects in 40 CFR Parts 704 and 799

Chemicals, Chemical fate, Chemical export, Environmental effects, Environmental protection, Hazardous substances, Health, Laboratories, Recordkeeping and reporting requirements, Testing, Incorporation by Reference

Dated: December 26, 1991.

Victor J.Kimm, ActingAssistant Administrator for Prevention, Pesticides andToxicSubstances.
Therefore, it is proposed that 40 CFR Chapter Ibe amended as follows: 

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1. In part 704:



### PART 704-[AMENDED]

a. The authority citation for Part 704 would continue to read as follows:

Authority: 15 U.S.C. 2607


### b. By adding §704.32 to read as follows:
§704.32 Aryl Phosphate Base Stocks.



### (a)Substances for which reportingis required.The chemical substances for which reporting is required under this rule consist ofthe category of aryl phosphate base stocks, as defined in §799.700 ofthis chapter, that are now listed on, orin the future are added to, the public orconfidential portions ofthe TSCA Inventory ofChemical Substances maintained by EPAunder TSCA section 8(b) at any time after the effective date of the final rule.New chemical substances meeting this definition shall also be subject to this section once entered into the TSCA Inventory ofChemical Substances.

(b) Persons who must report.The following persons, unless exempt as provided in §704.5, are subject to the reporting requirements ofthis rule; a person may be required to report more than once under this section. Those persons who are small manufacturers as defined in §704.3 are also required to report.

(1) Initialreporting. Persons who 

### manufacture orimport any substance identified in paragraph (a) ofthis section for commercial purposes during the person's latest complete corporate fiscal year priorto (theeffective date of the final rule) are required to report.

(2) Subsequent reporting. Persons who 

### manufacture orimport any substance identified in paragraph (a) ofthis section for commercial purposes after (the effective date ofthe final rule) are required to report. The persons described in thisparagraph (b)(2) include persons who report initially in response toparagraph (b)(1) ofthis section and persons who commence the manufacture or importation ofany substance identified in paragraph (a) of this section after (the effective date of the final rule).

(c) When to report-(1) Initial reporting. Persons described in 

### paragraph (b)(1) of this section must submit an initial report within 60 

### days of (theeffective date ofthe final rule).

(2)Subsequentreporting. Persons described in paragraph (b)(2) ofthis section must submit a report within 60 days ofthe completion ofeach corporate fiscal year during which they manufacture or import any substance identified in paragraph (a)of this section. Persons shall submit a separate report for each corporate fiscal year in which they are subject to this section.

(3)Duplicativereporting. Persons reporting under this section are exempt, pursuant to §710.35 of this chapter, from duplicative reporting for the Inventory Update Rule. (d) What information to report. All persons subject to this section shall report the following information to EPA:

(1)

### Company name and headquarters address.

(2) 

### Name, address, and telephone number (including area code) of the company's principal technical contact.

(3)

### The chemical name and Chemical Abstracts Service Registry Number (CAS number)ofeach chemical substance identified inparagraph (a) of this section manufactured or imported during the latest complete corporate fiscal year. (4)

### The quantity (in pounds) ofeach such substance manufactured or imported during the latest complete corporate fiscal year.

(5)A crossreference to any letter of intent to test thathas been submitted for that substance under 40 CFR 799.700(d).

(e) Where to sendreports. Reports
mustbe submitted to the U.S. Environmental Protection Agency, TSCA Document Processing Center (TS790), Rm. L-100, Office ofPollution Prevention and Toxics, 401 M St., SW., Washington, DC 20460, Attn: TSCA section 4, Aryl phosphates.

2. In Part 799:



### PART799--[AMENDED]

a. The authority citation for part799 would continue to read as follows:

AUTHORITY: 15 U.S.C. 2603, 2611, 2625. 

### 2.By adding §799.700 to read as follows:
§799.700 Arylphosphate base stocks.



### (a)Scope andpurpose.This section requires persons who manufacture, import, or process a chemical substance in the "aryl phosphate base stocks" chemical category to conduct chemical analysis and testingfor health effects, environmental effects, and chemical fate ofthe substance. The extent oftesting for an individual aryl phosphate base stock depends upon its aggregate annual production volume. The testing requirements are divided intotwo stages. Stage one,which is required of all manufacturers, importers, and processors, involves chemical analysis that will determine the chemical identity ofthebase stocks produced during the period thisrule is in effect. Stage two, which is subdivided intothree levels triggered by production volume, involves testing forhealth and environmental effects, and chemical fate.

(1)Stage one. (i)All persons who manufacture, import, orprocess, or intend to manufacture, import, or process a particular aryl phosphate base stock will be responsible for conducting chemical analysis of that substance

- pursuant to paragraph (e) of this section. (ii) From theresults ofthese analyses, EPAwill determine whether two or
more chemicals are equivqlent and whether further tests can bejointly sponsored. For purposes ofthis section, base stocks with greater than 2percent variation in a single component (0.1 

### percent for TOCP) will be considered different base stocks. As provided in paragraph (d)(3) ofthis section affected persons will be notified ofsuch decisions by certified mail.

(2) 

### Stage two-(i) Level 1.When the aggregate annual production volume for all manufactures and importers ofa particular aryl phosphate base stock is,

or reaches, 1million pounds, all persons who manufacture, import, or process that substance willbe responsible for conducting the following testing ofthe substance pursuant to paragraphs (g)(1)(ii), (h)(2)(i)(B) and (h)(3)(i) ofthis section: a 120-day post-hatch rainbow trout early life stage (ELS) test, three hen neurotoxicity assays, and a twogeneration reproductive effects study.

(ii) Level2. When the aggregate annual productionvolume forall manufacturers and importers ofan aryl phosphate base stock substance is, or reaches, 5million pounds, all persons who manufacture, import,or process that substance will be responsible for conducting the following testing of the substance pursuant to paragraphs (f)(1), (g}€1l(i} (g}(1}{ii}, (h)(1), {h}{2}Ci}CB}, and (h)(3)(i) ofthis section: all Level 1testing plus anaerobic biodegradation, chronic Daphnia, and subchronic toxicity studies.

(iii) Level3.When the aggregate annual production volume for all manufacturers and importers ofan aryl phosphate base stock substance is, or reaches, 10 million pounds, all persons who manufacture, import, orprocess that substance will be responsible for conducting the following testing ofthe substance pursuant to paragraphs (f), (g), and (h) ofthis section: all Level 1 and Level 2testingplus aerobic biodegradation, a microcosm ecosystem test, and developmental toxicity studies, and the subchronic ratneurotoxicity battery.

(b) Definitions. In addition to the definitions in section 3ofTSCA and the definitions of §790.3 of this chapter, the 

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## / Friday, January 17, 1992 / Proposed Rules

following definition also applies tothis section.

(1)"Aryl phosphate base stocks" are phosphate esters or combination of
esters resultingfrom the reaction ofa phenol,mixtures ofphenols, ora combination ofalkyl-substituted phenols or,in some cases, phenols plus

an alcohol, withphosphorus oxychloride (POCi 3

### )orother phosphoric acid derivatives. This definition includes triaryl and mixed aryl/alkyl esters (whereone ortwo ofthe three ester groups are alkyl).

(2)[Reserved) (c)Identificationoftestsubstance.(1) This section applies to any chemical substance within the aryl phosphate base stock category. The chemical substances in this category listed on the TSCA section 8(b) public inventory are identified in thisparagraph. Any aryl phosphate base stock substance that
meets the category definition in paragraph (b)(1) ofthis section shallbe tested in accordance with this section. Base stocks differing from one another by more than2 percent in a single component (0.1 percent forTOCP) shall be considered different base stocks for purposes of this rule.

(2) This section also applies to any
new chemical substance withinthe aryl phosphate base stock substance category. Persons subject to this section byvirtue oftheir intention to manufacture or import a new chemical substance in thecategory of aryl phosphate base stock substances must comply with this section before submitting a premanufacture notification (PMN) under TSCA section 5(a) for such substance.

(3)Thefollowing currently manufactured base stock substances meet the category definition and shall be tested:

(i)tert-butylphenyl diphenyl phosphate (CAS No. 56803-37-3), or isobutylenated phenol, phosphate (3:1) (CAS No. 68937-40-6) (based on a 1:3 

### mol ratio isobutylene tophenol).

(ii) bis-(tert-butylphenyl) phenyl phosphate (CAS No. 65652-41-7), or isobutylenated phenol, phosphate (3:1) (CAS No. 68937-40-) (based on a 2:3 mol ratio isobutylene tophenol).

(iii) tris-(tert-Butylphenyl) phosphate (CAS No. 78-33-1), orisobutylenated phenol, phosphate (CAS No. 68937-40-6) (basedon a 1:1 mol ratio isobutylene to phenol).

(iv)Di-n-butyl phenyl phosphate (CAS No. 252&-36-1-).



### (v)2-ethylhexyl diphenyl phosphate (CAS No. 1241-94-7).



### (vi)Isodecyl diphenyl phosphate (CAS No. 29761-21-5). (vii) lsopropylphenyl diphenyl phosphate (CAS No. 28108-99-8). or phenol, isopropylated, phosphate (3:1) (CAS No. 68937-41-7) (based on a 1:3 mol ratiopropylene to phenol).

(viii) bis-(Isopropylphenyl) phenyl phosphate (CAS No. 28109-00-4). or phenol, isopropylated, phosphate (3:1) (CAS No. 68937-41-7) (based on a 2:3 mol ratio propylene to phenol).

(ix) tris-(Isopropylphenyl) phosphate

or phenol, isopropylated, phosphate (3:1) (CAS No. 68937-41-7) (basedon a 1:1 mol ratio propylene to phenol).

(x) Tricresyl phosphate (CAS No. 1330-78-5), or tar acids, cresylic, phenyl phosphate (CAS No. 68952-35-2)

(xi) Triphenyl phosphate (CAS No. 115-8)-6).

(xii) Trixylyl phosphate (CAS No. 25155-23-1), or tar acids, cresylic, C-8 rich, phenyl phosphate (CAS No. 68952- 33-6).

(d) Personsrequired to submitstudy plans,conduct tests,submitdata,and theEPA notification plan-(1)Chemical analysis.All persons who manufacture (including persons who import) or process or intend tomanufacture or process any aryl phosphate base stock substance that meets the definition in paragraph (b)(1) of this section including, but not limited to, those listed in paragraph (c)(3) of this section,from the effective date ofthis section to the end ofthe reimbursement period, are subject to chemical analysis testing and shall submit letters ofintent to test. submit study plans, conduct tests and submit data as described in this section, subpart A ofthis part, and parts 790 and 792 ofthis chapter for single-phase rulemaking.

(2) Chemical fate,environmental effects and healtheffects tests.All
persons who manufacture, import or process, or intend to manufacture, import orprocess any aryl phosphate base stock substance that meets the definition in paragraph (b) ofthis section, from the effective date ofthis section to the end of thereimbursement period, shall submit letters ofintent to test, submit study plans, conduct tests and submit data as described in this section, subpart A ofthis part, and parts 790 end 792 ofthis chapter for singlephase rule-making.

(e) Chemical analysis-(1) Required testing.GC/MS analysis shall be performed on every aryl phosphate base stock substance. Theprovisions of § 792.105(a) ofthis chapter require that for each study done under Good Laboratory Practice Standards, the identity, strength, purity and composition stability shall be determined for each batch and shall be documented before the initiation ofthe study. Any individual aryl phosphate positional isomer, except tri-ortho-cresyl phosphate (TOCP),or any other substance present in a base stock, must be identified and quantitated ifpresent
at a concentration ofI percent or greater, quantitation is required to ±0.5 percent.TOCP shall be quantitated, at ±0.05 percent, unless present at less than 0.10 percent.

(2)Reportingrequirements. Chemical analysis shall be completed and the final report submitted toEPA no later than 6 months after the effective date of this test rule or,for new chemicals, with the Premanufacture Notification under TSCA section 5(a).

(3)EPA notificationof manufacturers. The Agency will notify manufacturers by certified mail iftheir chemical is equivalent to another manufacturer's and costs may be shared, or ifthey are required tobegin additional testing under this test rule without co-sponsors. The notification will also include for each manufacturer the level oftesting that should begin forthe specific aryl phosphate base stock substance and will specify which ofany equivalent substances must be tested.

(f) Chemical fate-(1)Required testing--i)Anaerobic biodegradation testing shall be performed inaccordance with § 798.3140 of this chapterupon receipt ofEPA's written notification to manufacturers, pursuant toparagraph (e)(3) ofthis section, ofa particular aryl phosphate base stock substance that EPA has determined that the aggregate annual production volume ofthat substance equals or exceeds 5 million pounds.

(ii) Aerobic biodegradation testing shall be conducted using clean freshwater sediments in accordance with the method described in an article by Bourquin (1977) entitled "An Artificial Microbial Ecosystem for Determining Effects and Fate of Toxicants in a Salt-Marsh Environment", published in DevelopmentsinIndustrial Microbiology,voL 18 Chapter 11, 1977, which Is incorporated by reference. A
copy ofthis material incorporated by reference is available in the TSCA Public Reading Room, Rm. NF-G04,401 M St., SW., Washington, DC 20460. This material is also available for inspection
at the Office ofthe Federal Register, Rm. 8401, 1100 L St., NW., Washington, DC
20408. This incorporation by reference

was approved by the Director of the Federal Register in accordance with 5
U.S.C. 552(a) and I CFR part 51. This method is incorporated as it exists on the effective date ofthis section and notice ofany change to the method will 

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be published in the Federal Register. The aerobic biodegradation test is required upon receipt ofEPA's written notification to manufacturers, pursuant to paragraph (e)(3) of this section, of a particular aryl phosphate base stock substance that EPAhas determined that the aggregate annual production volume of that substance equals or exceeds 10 millionpounds.

(2)Reportingrequirements.{i) Each chemical fate test shall be completed and the final report submitted to EPA within 12 months after receipt ofEPA's written notification that the anaerobic biodegradation or the aerobic biodegradation testing mustbe initiated.

(ii)Progress reports shall be submitted to EPA at 6-month intervals, beginning 6 months after receipt ofEPA's written notification that testing must be initiated until submission ofthe final report.

(g)Environmental effects-(1) Requiredtesting--(i Daphnid chronic toxicity test.The chronic test for 

### Daphnia shall be performed according to §797.1350 ofthis chapter uponreceipt of EPA's written notification to manufacturers, pursuant to paragraph (e)(3) ofthis section,of a particular aryl phosphate base stock substance that EPA has determined that the aggregate annual production volume of that substance equals or exceeds 5million pounds.

(ii)FishELS toxicitytest.(A) The ELS test for aquatic toxicity in the rainbow trout shall be performed according to §797.1600 ofthis chapter, except the provisions ofparagraph of §797.1600(c)(1)(i), upon receipt ofEPA's written notification to manufacturers, pursuant toparagraph (e)(3) ofthis section, ofa particular arylphosphate base stock substance thatEPA has determined that the aggregate annual production volume ofthat substance equals or exceeds 1million pounds.

(B) For the purpose ofthis section, the following provisions also apply:

(1)

### The test terminates following 120 days ofpost-hatch exposure (for an approximate total exposure period of 150days).

(2)[Reserved] 

### (iii) Generic freshwatermicrocosm test.Thegeneric freshwater microcosm
test shall be performed according to proposed § 797.3050 (52 FR 36344, 

### September 28, 1987) upon receipt of EPA's written notification to manufacturers, pursuant to paragraph (e)(3) ofthis section, ofa particular aryl phosphate base stock substance that EPA has determined that the aggregate annual production volume of that substance equals or exceeds 10 million pounds. (2)Reportingrequirements.(i)The Daphnid chronic toxicity test shall be completed and the final report submitted
toEPA within 12 months after receipt of EPA's written notification that testing
must be initiated.

(ii) The fish ELS test in the rainbow
trout shall be completed and the final report submitted to EPA 18 months after receipt ofEPA's written notification that testing must be initiated.

(iii) The generic freshwater microcosm
test shall be completed and the final report submitted toEPA 24 months after receipt ofEPA's written notification that testing must be initiated.

(iv) Progress reports shall be submitted to EPA at 6-month intervals, beginning 6 months after receipt of EPA's written notification that testing
must be initiated until submission ofthe final report

(h) Healtheffects-(1) Subchronic toxicity.-(i)Requiredtesting.(A) Oral toxicity testing in the Sprague-Dawley
rat shall be performed by gavage in accordance with § 798.2650 ofthis chapter, except the provisions of §798.2650(e)(9)(i)(B), upon receipt of EPA's written notification to manufacturers, pursuant to paragraph (e)(3) ofthis section, ofa particular aryl phosphate base stock substance that EPA has determined that the aggregate annual production volume of that substance equals or exceeds 5 million pounds.

(B) For the purpose ofthis section, the following provisions also apply:

(1)Blood acetylcholinesterase activity shall be determined pre-dosing, and blood and brain acetylcholinesterase activity at termination.

(2) [Reserved] (ii)Reportingrequirements-(A) Subchronic toxicity testing shall be completed and a final report submitted to EPA within 18 months after receipt of EPA's written notification that testing
must be initiated.

(B) Progress reports shall be submitted
to EPA at 6-month intervals, beginning 6 months after receipt ofEPA's written notification that testing must be initiated until submission ofthe final report.

(2) Neurotoxicity-(i) Required testing.(A) Gavage neurotoxicity testing in the Sprague-Dawley rat shall be performed according to § § 798.6050, 798.6200 and 798.0400 ofthis chapter upon receipt ofEPA's written notification to manufacturers of a particular aryl phosphate base stock substance that EPA has determined that the aggregate annual production volume ofthat substance equals or exceeds 10 million pounds (see paragraph (e)(3) of this section). Tests conducted according
to §798.6050 and § 798.6200 ofthis 

### chapter shall be both acute and subchronic. The test conducted according to §798.6400 ofthis chapter shall be subchronic. The acute studies according to §798.6050 and §798.6200 of 

### this chapter may be incorporated into the subchronic neurotoxicity tests. The subchronic neurotoxicity tests may be combined with the testing required by paragraph (h)(1)(i) ofthis section ifthe test protocol allows. The cited guidelines provide standard information for these procedures.

(B) Gavage neurotoxicity testing in the hen shall be performed according to § § 798.6450, 798.6540, and 798.6560 of 

### this chapter upon receipt ofEPA's written notification to manufacturers of

a particular aryl phosphate base stock substance that EPAhas determined that the aggregate annual production volume of that substance equals or exceeds 1 million pounds (see paragraph (e)(3) of this section). Testing according to §798.6450 of this chapter shall be performed in conjunction with §798.6540 of this chapter. However, if results for a substance tested according

to § 798.6540 and § 798.6450 ofthis 

### chapter are negative, then testing according to §798.6560 of this chapter need not be conducted on that substance.

(ii)Reportingrequirements-A)Rat neurotoxicity studies shall be completed 

### and the final reports submitted toEPA within 18 months after receipt ofEPA's written notification that testing must be initiated until submission ofthe final report.

(B) The henneurotoxicity studies pursuant to §798.6450 and §798.6540 of this chapter shall be completed and final reports submitted to EPA within 6 months afterreceipt ofEPA's written notification that testing must be initiated. Ifthe subchronic study, §798.6560 ofthis chapter as specified in paragraph (g)(2)(i)(B) ofthis section, is necessary, the final reporting date will be 18 months after receipt ofEPA's written notification that testing mustbe initiated.

(iii) Progress reports shall be submitted to EPA at 6-month intervals, beginning 6months afterreceipt of EPA's written notification that testing must be initiated until submission ofthe final report.

(3) Reproductionand fertility-(i) Requiredtesting.(A) Reproduction and fertility testing shall be performed by 

### gavage in the Sprague-Dawley rat according to §798.4700 ofthis chapter, except the provisions ofparagraphs (c)(7)(i), (c)(8)(ii), (c)(9)(i) and (c)(9)(iii) of §798.4700, upon receipt ofEPA's written notification to manufacturers, 

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pursuant to paragraph (e)(3) ofthis section, ofa particular aryl phosphate 

### base stock substance that EPAhas determined that the aggregate annual production volume ofthat substance equals orexceeds I million pounds.

(13) For the purposes ofthis rule, the following provisions apply:

(1)Data on female cyclicity inP and F, females over the last 3weeks prior to mating shall be described. The method of Sadleir (1979], found under paragraph (i)(6) of this section, or an equivalent method may be used.Data shall be provided on whether the animal is cycling and the cycle length. P andF, females shall continue to be exposed to the test substance through the 3weeks prior to mating. The ovary shall be serially sectioned with a sufficient number ofsections examined to adequately detail oocyte and follicular morphology. The methods ofMattison and Thorgierson (1979] foundunder paragraph (i)(3) ofthis section and Pederson and Peters (1988) found under paragraph (i)(4) of this section ortheir equivalent provide guidance. The strategy forsectioning and evaluation is left to the discretion ofthe investigator, but shall be described in detail in the test protocol and final report.

(2)Measurements ofhomogenizationresistant spermatid count, caudal epididymal sperm density and motility will beprovided. Assessments of motility include quantification of progressively motile and immotile sperm, and techniques thatutilize video recording ofthe samples, as well as objective measurement ofthe motility parameters. Guidance for assessing motility is provided by Under et al. (19806) found under paragraph (i)(2)of this section, and Klinefelter et al. (1991) found under paragraph (i)(1) ofthis section, ortheir equivalent.

(3] Weights ofthe testes, epididymes (total and cauda), pituitary, seminal vesicles (with coagulating glands), prostate, ovary and uterus shall be recorded at thetime ofsacrifice ofthe P and F animals. Histopathology of the testes shall be conducted on the P and F

1

### males at the time ofsacrifice. Particular attention shall be directed toward achieving satisfactory quality from fixation and embedding, and preparations shall follow the recommendations ofRussell etal. (1990) found under paragraph (i)(5) ofthis section, oran equivalent. Histologic analyses shall include evaluations ofthe spermatogenic cycle,i.e.. thepresence and integrity of the 14 cell stages. These evaluations followthe guidance provided by Russell etal. (1990) found underparagraph (i)(5) ofthis section, or
an equivalent.

(ii) Reportingrequirements-(A)The 

### reproductive and fertility studies shall be completed and final reports received by the EPA 24 months afterreceipt of EPA's written notification that testing must be initiated.

(B) Progress reports shall be submitted to EPA at 6-month intervals, beginning 6 months after receipt ofEPA's written notification that testing mustbe initiated until submission ofthe final report.

(4)Developmentaltoxicity-(i) Requiredtesting.Developmental 

### toxicity studies shall be performed by gavage in therat and rabbit according to §798.4900 ofthis chapter upon receipt of EPA'swritten notification to manufacturers, pursuant to paragraph (e)(3) ofthis section, ofa particular aryl phosphate base stock substance that EPA has determined that the aggregate annual production volume of that substance equals orexceeds 10 million pounds.

(ii) Reportingrequirements-(A)The 

### developmental toxicity studies shall be completed and final reports submitted to EPA within 12 months after receipt of EPA's written notification that testing
must be initiated.

(B)Progress reports shall be submitted
to EPA at 6-month intervals, beginning 6 months after receipt ofEPA's written notification that testing must be initiated until submission ofthe final report.

(i) References.For additional background information, the following references should be consulted.

(1)Klinefelter, G.R., Gray,L.E., Jr. andJ.D. Suarez. "The method ofsperm collection significantly influences spermmotion parameters following ethane dimethanesulfonate administration in the rat." ReproductiveToxicology.5:39-45 (1991).

(2)Linder. R.E.. Shrader, L.F. and W.K. McElroy. "Measurement ofepididymes sperm motility as a test variable in the rat." Bulletin ofEnvironmentalContaminantToxicology. 36:317-324 

### (1986).

(3)Mattison, D.R. and Thorgeirsson, S.S. "Ovarian arylhydrocarbon hydroxylase activity endprimordial oocyte toxicity of polycyclicaromatic hydrocarbons in mice." Cancer Research.39-.3471-3475 (1979). (4)Pederson. T.and Peters. H. "Proposal forclassification ofoocytes and follicles in the mouse ovary."JournalofReproduction and Fertility.17:555-557 (1968). (5)Russell. LD.. R.A. Ettlin. Sinha Hikim, A.P. and E.D.Clegg. "Histological and histopathologic evaluation ofthe testis." Cache River Press: Clearwater,FL (1990).

(6) Sadleir, R.M.F.S. "Cycles and seasons." In:ReproductioninMommals: I. GermCellsand Fertilization, Austin, C.R. and R.V. Short, eds. Cambridge Press: New York, NY (1979).



### (j)Effective date.(1)The effective date ofthe final rule will be (insert date 44 days after date ofpublication offinal rule in the Federal Register).

(2) The guidelines cited in this section

are referenced here as they exist on (inserteffective date ofthe finalrule). (Information collection requirements have been approved by the Office ofManagement and Budget under controlnumber 2070-0033.)

[FR Doc.92-1200 Filed 1-16-92 8:45 am]

BILLING COOE 6560-60-F 

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