EPA’s First Existing Chemical Assessment under the Amended TSCA Finds No “unreasonable risk”

News & Events

November 20, 2018

The US Environmental Protection Agency (EPA) has just released the first draft risk evaluation of an existing chemical under the accelerated program of evaluations mandated by the 2016 amendments to the Toxic Substances Control Act (TSCA). The new assessment of Pigment Violet 29 is the first to appear among the “first 10” chemicals named by the agency in 2016 as its initial priorities for existing chemical assessment. There will be a 60-day public comment period as well as a peer review by the TSCA Science Advisory Committee on Chemicals (SACC), which will be this new advisory committee’s first encounter with an assessment under the amended TSCA.

This first case will be examined closely for what it reveals about EPA’s approach to – and standards for – implementing the broadly phrased mandates of the amended statute and its enabling Risk Evaluation Process Rule. There have already been debates about how to implement mandates for “best available science” and a “weight-of-evidence” approach, as well as how to consider the array of foreseeable uses requiring risk evaluation under the statute. The nature of public comments, EPA’s response to them, and the views expressed in the SACC peer review will all signal what’s to come for the rest of the “first 10” chemicals, whose assessments must be completed by December 2019. 

EPA’s evaluation of Pigment Violet 29 concludes that there are no exposures posing concern for “unreasonable risk.” This is based largely on the lack of significant exposure – owing to uses in contained settings, low vapor pressure, and poor ability to be absorbed – along with toxicity information that indicates lack of toxic effects at low and moderate exposure levels. This was taken by the agency as obviating the need for detailed evaluations of exposure pathways – an approach that was first proposed for Pigment Violet 29 in the Scoping document for this chemical that was released in June 2017. A key element to note is that much of the toxicity information comes from reports claimed as confidential business information (CBI); consequently, EPA has seen information in detail that will not be available to the general public. EPA used summaries of studies submitted to the European Union (EU) for chemical registration under the EU’s Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) legislation, but these studies are also only available to the public in summary form. Moreover, some of the conclusions of low toxicity are based on structure-activity relationships (SAR), rather than from bioassay testing. 

Presumably, Pigment Violet 29 was chosen as the initial case because a fairly clear “no unreasonable risk” finding was supportable without very complex analysis, but many of the remaining chemicals among the “first 10” will not have such a ready path. How this first example is received by stakeholders and the SACC reviewers will be telling for the risk evaluation process. Gradient continues to help clients navigate the new TSCA chemical prioritization and risk evaluation processes and will continue to keep clients informed of significant TSCA milestones. Please contact us if you have any questions about how the risk evaluation process may affect your business. 

Gradient Contacts:

Lisa A. Bailey, Ph.D.
Senior Toxicologist

Jessie M. Kneeland, Ph.D.
Senior Environmental Chemist

Ari S. Lewis, M.S.

Heather N. Lynch, M.P.H.
Senior Toxicologist

Jiaru Zhang, M.P.H.
Senior Toxicologist

Lorenz R. Rhomberg, Ph.D., ATS


Gradient is an environmental and risk sciences consulting firm renowned for our specialties in Toxicology, Epidemiology, Risk Assessment, Product Safety, Contaminant Fate and Transport, Industrial Hygiene, Geographic Information Systems, and Environmental/Forensic Chemistry. We employ sound science to assist national and global clients in resolving their complex problems relating to chemicals in the environment, in the workplace, and in consumer products.