TSCA and Exposure Assessment: Testing Requirements

Continuing the series on TSCA and exposure assessment, today’s blog post is about the testing requirements for chemical substances in TSCA.

15 CFR 53 Part 2603(a) explains the testing requirements. This is best explained in a graphic (made by me and you're welcome to use it):

Flowchart of TSCA Testing Requirements

If a chemical fits the requirements explained in the image above, the Administrator (of the U.S. Environmental Protection Agency) will call for testing to be conducted on the substance or mixture. The testing must show whether the manufacture, distribution, processing, use, or disposal (or any combination of these activities) DOES or DOES NOT present an unreasonable risk of injury to health or the environment.

The Administrator can also require the development of new information relating to a chemical substance or mixture – this is at the discretion of the Administrator, to establish the priority (either high-priority or low-priority) of the substance or mixture. This prioritization is established to rank substances or mixtures for risk evaluation by the U.S. Environmental Protection Agency.

A high-priority substance is one that presents an unreasonable risk of injury to health or the environment because of a potential hazard or a potential route of exposure under normal conditions of use. The definition for high-priority substance has more worrisome language, however. The Administrator can conclude that a substance is a high-priority substance without consideration of costs or other non-risk factors, and the Administrator decides which potentially exposed or susceptible subpopulation is relevant in determining whether the substance poses an unreasonable risk (emphases added).

A low-priority substance is anything that the Administrator deems not to be a high-priority substance, based on information sufficient to establish this designation, without consideration of costs or other non-risk factors. “Information sufficient to establish” is not defined.

This puts a significant amount of authority on the Administrator - to decide which substances are high priority (or not), to decide which potentially exposed subpopulation is worth protecting, or what information and data is sufficient to establish the priority level. 

If the Administrator requires the development of new information, the Administrator must write a statement of need. This statement must include: 1) the need for the new information, 2) how information reasonably available to the Administrator was used to inform the decision, 3) explanation of any decision requiring the use of vertebrate animals for testing, and 4) why the issuance of an order is warranted rather than promulgating a rule or entering into a consent agreement.

One big issue here is “information reasonably available” to the Administrator – how is this to be decided? What constitutes reasonably available? How substantial of a data search or literature review is this?

Any rule, order, or consent agreement must include the following basic information:

• Identification of the chemical substance or mixture
• Protocols and methodologies for the development of information for each substance or mixture
• A specified time period (which may not be of unreasonable duration) where the person(s) required to conduct the testing must report the information to the Administrator

It also states the Administrator’s considerations for testing must include the relative costs of test protocols and methodologies, as well as the reasonably foreseeable availability of facilities and personnel needed to perform the testing under the rule. This may require the person(s) or facility to submit preliminary information to the Administrator.

Last post we discussed the health and environmental effects that would necessitate development of information – carcinogenesis, mutagenesis, teratogenesis, behavioral disorders, cumulative or synergistic effects, and any other effect that may present an unreasonable risk of injury to health or the environment.

The regulation also calls out specific characteristics of chemicals or substances that would necessitate development of information – persistence, acute toxicity, subacute toxicity, chronic toxicity, and any other characteristic that may present such a risk.

The inclusion of “any other characteristic” that may present an unreasonable risk is nonspecific and will likely present confusion for manufacturers in evaluating the risks of their substances or mixtures.

Protocols and methodologies that may be prescribed by the Administrator include epidemiologic studies, serial or tiered testing, in vitro tests, and whole animal tests. The regulation notes: “before prescribing epidemiologic studies of employees, the Administrator shall consult with the Director of the National Institute for Occupational Safety and Health” (NIOSH). This proposed practice may lead to privacy concerns for employees who may be required to participate in the epidemiological studies.

A goofy phrase in the regulation can be found in Part 2603(b)(2)(B), where it says: “from time to time, but not less than once each 12 months,” the Administrator must review any protocols or methodologies developed in response to a rule, order, or consent agreement for adequacy. This "from time to time" phrase makes no sense in a regulatory document. And again, the definition of “adequate” is not provided.

When creating the priority list, the Administrator has to consider at least the following information:

• The quantities of the substance that are or will be manufactured
• The quantities of the substance that are or will enter the environment
• The number of individuals that are or will be exposed to the substance in their place of employment, including the duration of such exposure
• The extent to which human beings are or will be exposed to the substance
• The extent to which the substance is closely related to another chemical substance which is known to present an unreasonable risk of injury to health or the environment
• The extent to which testing of the substance may result in the development of information upon which the effects of the substance on health or the environment can reasonably be determined
• The reasonably foreseeable availability of facilities and personnel for performing testing on the substance

The delineation of “individuals” that are or will be exposed in their place of employment versus “human beings” is unintentionally funny, as if individuals who work are somehow separate from the rest of humanity.

The regulation requires a committee to be established to make recommendations to the Administrator re: priority substances. The committee must give priority attention, per the regulation, to substances and mixtures that are carcinogens, mutagens, or teratogens. If the Administrator receives information about a substance that concludes the substance presents a significant risk of serious or widespread harm to human beings, the Administrator has 180-days to initiate “applicable action” to “prevent or reduce to a sufficient extent such risk.” 

Who decides what level of risk reduction is "sufficient" in this case? The words used in this regulation could easily be subject to interpretation an argument: unreasonable, sufficient, reasonably available, adequate, individuals, human beings, foreseeable, etc. 

Something interesting in the testing section is the requirement to reduce testing on vertebrates, and to use alternative testing methods whenever feasible. This can include:

• Computational toxicology and bioinformatics
• High throughput screening methods
• Testing of categories of chemical substances
• Tiered testing methods
• In vitro studies
• Systems biology
• Other new or revised methods identified by validation bodies

In my next post, I’ll go over the manufacturing section, including the requirement for “protection against unreasonable risks” per TSCA. Future posts will include the following topics:

• Manufacturing and protection against unreasonable risks
• Risk evaluation in TSCA
• Imminent hazards in TSCA
• Reporting requirements of TSCA
• Research aspects of TSCA
• How TSCA handles confidential information
• Citizen’s civil actions and petitions in TSCA
• Employee protection and TSCA effects on employment
• How test methods will be developed and evaluated for TSCA
• ReachScan: the exposure assessment model
• Using predictive methods to assess exposure 
• New chemical exposure limits under TSCA