Risk assessment testing requirements

An obvious and all-important aspect of Section 8 is that it is a mechanism to facilitate the acquisition of information that EPA needs. Accordingly, the proper test of EPA s performance under Section 8 is not the amount of information that EPA acquires or the number of companies required to report, but the Agency s success in building a data-base for accomplishing its specific risk assessment, testing and chemical control responsibilities under Sections 4, 5, 6 and 7 of TSCA. In view of this purpose, it was of great concern that EPA has repeatedly failed to define carefully, and then articulate fully, the connection between a proposal under Section 8, and a specific regulatory objective under some other provision of TSCA. 

Institutional Transition. Adopting a new paradigm for toxicity testing and risk assessment will require changes to the EPA s operations, organization, and outreach. The ERA is expecting that this transition will likely require more than a decade for full implementation. 

It should be understood that to develop process metrics based on a credible risk assessment will require a considerable number of tests to assess appropriately the potential environmental hazards associated with the process and the materials used in the process. One typically needs to screen compounds to assess their environmental hazard and their tendency for persistence, bioaccumulation, and toxicity. Depending on how a compound is ultimately used, environmental testing might lead you to the conclusion that it is best to avoid the commercial production of a particular compound. Alternatively, you might devise a process that uses the compound but controls the environmental risk to acceptable levels. For the latter case, performing a process-specific risk assessment would be imperative to assess the impact of the inherent hazard and environmental fate and effects of a given chemical or set of chemicals. In addition, the unique characteristics of the process, available treatment, and volumes will need to be taken into consideration. 

However, as the committee has noted, a waste-specific (and in certain circumstances, a site-specific) determination of the safety and efficacy of incineration must be made before an incinerator can be permitted to treat non-stockpile chemical materials (NRC, 1999a). Such a risk assessment is required by EPA regulations and guidance on stack emission testing of combustion emission sources (EPA, 2001b). 

An appropriate risk assessment is required where the hazard quotient is >50, further testing may be required (see above). 

The SAR does not utilize an analysis worksheet since it is a summary document of safety analyses, risk assessments, test results, and safety studies already performed. As a minimum, the following basic information is required from the SAR document ... 

U.S. EPA s recommendations regarding stack emission tests, which may be performed at hazardous waste combustion facilities for the purpose of supporting MACT standards and multipathway, site-specific risk assessments, where such a risk assessment has been determined to be necessary by the permit authority, can be found in the U.S. EPA document on Risk Burn Guidance for Hazardous Waste Combustion Facilities.32 The applicability of the new standards has been demonstrated in the management of hazardous waste incinerators, whose performance was shown to clearly surpass the regulatory requirements in all tested areas.33... 

Most of the provisions of the Toxic Substances Control Act (TSCA) of 1976 (PL 94-469) rely in some way on risk assessment of chemicals. Under the reporting requirements of the statute, any manufacturer, processor, or distributor of a chemical for commercial purposes must inform the EPA immediately after discovering any information which "reasonably supports the conclusion" that a chemical substance or mixture "presents a substantial risk of injury to health or to the environment" unless the EPA Administrator has been adequately informed already. EPA is mandated to establish regulations for testing new or existing substances when it is determined that there is not enough health or environmental information, that testing is necessary to develop such information and that the chemical or mixture "may present an unreasonable risk of injury to health or the environment."... 

The dangerous properties of acute toxicity, irritation, corrosivity, sensitisation, repeated-dose toxicity and CMR are evaluated in terms of their potential toxic effects to workers, consumers and man exposed indirectly via the environment, based on the use for each stage in the lifecycle of the substance from which exposure can occur. Risk assessment is also required if there are reasonable grounds for concern for potential hazardous properties, e.g., from positive in vitro mutagenicity tests or structural alerts. The risk assessment involves comparing the estimated occupational or consumer exposure levels with the exposure levels at which no adverse effects are anticipated. This may be a quantitative risk assessment, based on the ratio between the two values, or a qualitative evaluation. The principles of human health risk assessment are covered in detail by Illing (a.30) and more briefly in Chapter 7 of (73). 

In what is being called the most far-reaching overhaul of European Union environmental policy ever, the European Commission released a draft policy proposal on May 7 that, if enacted, would require virtually all manufacturers of chemicals to provide risk assessments and other information regarding products they sell or ship into the EU. Chemicals would also have to be registered with the EC and many downstream users of products that contain chemical entities would have to file paperwork as well. The Registration, Evaluation and Authorisation of Chemicals, or REACH, proposal would apply to approximately 30,000 new and existing chemicals, and test data would have to be developed on some 5000 specific chemical entities, many of which have been commonly used for decades. EUROPEAN COMMISSION... 

In the five and one-half years of ensuing Congressional activity, many additional aspects were considered and some were included in the Act as finally enacted. Possibly the most controversial had to do with the treatment of new substances. Were these to be treated by registration, as is the case in the Federal Insecticide Fungicide and Rodenticide Act (FIFRA), or were they to be subject to a less onerous notification procedure This would begin the attempt to assess their risks more in balance with the growth in commercial volume of the substance, and hence with its capacity to pay the costs for the frequently costly testing required. Without such a balance, the... 

Following risk assessment, the next step is to draft a formal validation plan. This is a written plan that includes all the specific validation procedures, installation tasks, acceptance testing, documentation requirements, reviews and verification tasks that need to be followed for proper system validation. The plan should also define individual responsibilities for these tasks and include an expected timeline. The plan should be designed around the URS and take into account the risk assessment determinations performed earlier. 

Typically extrapolations of many kinds are necessary to complete a risk assessment. The number and type of extrapolations will depend, as we have said, on the differences between condition A and condition B, and on how well these differences are understood. Once we have characterized these differences as well as we can, it becomes necessary to identify, if at all possible, a firm scientific basis for conducting each of the required extrapolations. Some, as just mentioned, might be susceptible to relatively simple statistical analysis, but in most cases we will find that statistical methods are inadequate. Often, we may find that all we can do is to apply an assumption of some sort, and then hope that most rational souls find the assumption likely to be close to the truth. Scientists like to be able to claim that the extrapolation can be described by some type of model. A model is usually a mathematical or verbal description of a natural process, which is developed through research, tested for accuracy with new and more refined research, adjusted as necessary to ensure agreement with the new research results, and then used to predict the behavior of future instances of the natural process. Models are refined as new knowledge is acquired. 

Regulatory officials nevertheless act on the basis of such hypothetical risks ( hypothetical definitely does not mean imaginary it means that the risk estimates are based on certain scientific hypotheses and that they have not been empirically tested). Such actions are in part based on legal requirements (Chapter 11) and in part on the prudence that is a traditional feature of public health policies. The scientific information, assumptions, and extrapolation models upon which risk assessments are based are considered sufficiently revealing on the question of human risk to prompt risk-control measures. To put off such actions until it is seen whether the hypothesized risks are real - to wait for a human body count - is considered to be an unacceptable course. 

There are several large impediments to achieving the goal of more accurate risk assessments. First, it often requires a considerable investment in the research necessary to uncover the types of information needed to replace default assumptions in specific cases. If one hypothesizes that di-(2-ethylhexyl)phthalate (DEHP, a real and important chemical) produces liver tumors in rodents by mechanisms that either do not apply to humans at all, or that do not operate at low (human) doses, or both, then there arises the question of what type of research information is necessary to test the validity of such hypotheses If such research is actually carried out, then what type of results from that research would allow conclusions to be drawn about the validity of the hypotheses In many specific cases creative and knowledgeable scientists can hypothesize alternatives to the usual defaults and ways to test their validity. But it often turns out to be difficult to arrive at... 

It is sometimes claimed that the use of animal data for estimating human risk does not provide strong scientific support. However, because it is difficult to find alternative methods to test the direct toxic effects of chemicals, continuance of studies in animals is required for risk assessment of chemicals including PAEs. 

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