Threshold Requirements for Issuing Test Rules

TSCA 4(a) requires the EPA to issue rules requiring testing a chemical or mixture if either of two alternate sets of threshold requirements are met. The first set of threshold requirements focuses on the potential risk presented by the chemical and the second set focuses on potential exposure to the chemical. 

The risk-based requirements in 4(a)(1)(A), or A findings, require testing if the EPA finds that the manufacture, distribution, processing, use, or disposal of a chemical substance or mixture may present an unreasonable risk of injury to health or the environment. 

The exposure-based requirements in 4(a)(1)(B), or B findings, require testing if the EPA finds that (i) the chemical substance will be produced in substantial quantities and it is, or is expected to, be in the environment in substantial quantities or (ii) there is or may be significant human exposure. In either case, the EPA must also find two additional elements present before requiring testing (i) there is insufficient data on the chemical to determine or predict the effects of the chemical on health or the environment and (ii) testing is necessary to develop data to determine or predict its effects on health or the environment. And, in the case of a mixture, the EPA must find that it is not more efficient to test the components of the mixture than to test the mixture itself.  

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Section 4 of TSCA permits the EPA to require manufacturers and processors of chemicals that are already in production to test the chemicals they make and process. There are threshold determinations that the EPA must make before it can issue a test rule, and these deal with the risk that may be posed by the chemical, the extent of exposure to the chemical, and whether there is a genuine need for new data. The testing requirement of 4 looks mandatory on the surface—the EPA must require testing if the statutory preconditions are met. Of course, however, the EPA is afforded substantial deference when deciding if the preconditions are met. 

Once the EPA finds that the threshold requirements are present, it must issue a test rule that identifies the chemical or mixture and the test standards, and the due date for submitting testing results on existing chemicals. The test rule may require submission of prefiminary data before the testing is complete. ... 

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