In March 2012, US EPA unveiled a list of 83 priority “work plan chemicals” that are targeted for risk assessment and possible regulation in the next few years. Accompanying the list was a “Methods Document” that detailed the process US EPA used to select the list chemicals from the nearly 85,000 chemicals currently listed on its Toxic Substances Control Act (TSCA) Inventory. This list is the latest step by the US EPA in prioritization of chemicals for action as part of Administrator Lisa Jackson’s enhanced chemicals management initiative.
US EPA selected the 83 “work plan” chemicals through a two-step process. First, relying on internal and external data, the agency identified 1,235 chemicals that met one or more of the following criteria:
- Concern for children’s health (e.g., chemicals with reproductive or developmental effects).
- Persistent, bioaccumulative or toxic (PBT).
- Probable or known carcinogen.
- Used in children’s products.
- Used in consumer products.
- Detected in biomonitoring programs.
US EPA then excluded chemicals that are already regulated (PCBs) or that generally do not present significant health hazards (such as polymers).
These steps resulted in a list of 345 chemicals that were further assigned scores based on three characteristics: (i) hazard; (ii) exposure; and (iii) potential for persistence and/or bioaccumulation. The hazard analysis included toxicity, carcinogenicity and respiratory sensitization. The exposure review considered a combination of the chemical’s use in products, general population and environmental exposure and release information. The persistence scoring evaluated the half-life of a chemical in air, water, soil and sediment, and the bioaccumulation scoring relied on existing data on bioaccumulation/bio-concentration and, in some cases, modeling. The 83 “work plan” chemicals ranked high based on their scores. However, the list includes chemicals that may not present human health concerns but met criteria for identification as persistent, bioaccumulative and environmentally toxic.
Upon release of its list, US EPA also announced that it would be conducting risk assessments on seven of the chemicals this year, including:
- Antimony and antimony compounds
- HHCB (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8,-hexamethylcyclopenta[g]-2-benzopyran)
- Long-chain chlorinated paraffins
- Medium-chain chlorinated paraffins
Methylene chloride N-Methylpyrrolidone
The draft risk assessments for these chemicals are expected for public review and comment later this year.
US EPA followed up on June 1 and announced that it would conduct risk assessments on 18 more of the “work plan” chemicals during 2013 and 2014, including:
Five chlorinated hydrocarbons:
Three flame retardants:
− Bis (2-ethylhexyl)-3,4,5,6-tetrabromophthalate (TBPH) − 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB) − Tris (2-chloroethyl)phosphate (TCEP)
Four fragrance chemicals:
− Ethanone, 1-(1,2,3,4,5,6,7,8-octoahydro- 2,3,8,8-tetramethyl-2-naphthalenyl)-4-secButyl-2,6-di-tert-butylphenol
− Ethanone, 1-(1,2,3,4,5,6,7,8-octahydro- 2,3,5,5-tetramethyl-2-naphthalenyl)- − Ethanone, 1-(1,2,3,5,6,7,8,8a-octahydro-2,3,8,8- tetramethyl-2-naphthalenyl)- − Ethanone, 1-(1,2,3,4,6,7,8,8a-octahydro-2,3,8,8- tetramethyl-2-naphthalenyl)- 4-sec-Butyl-2,6-di-tert-butylphenol
P,p’-Oxybis (benzenesulfonyl hydrazide) Octamethylcycloetrasiloxane (D4)
While the risk assessments on these 18 chemicals will utilize the same data sources as the initial seven chemicals, US EPA is also encouraging interested parties to submit additional relevant information on the chemicals, such as unpublished studies or information on uses and potential exposures by August 31, 2012.
Additionally, US EPA will announce schedules for conducting risk assessments on other work plan chemicals at a later time, and it has also indicated that it will add to the priority list as more data is developed and other chemicals screened.
Any company that manufactures, imports, processes or uses any of the 83 priority chemicals should pay close attention to US EPA’s actions regarding them. This prioritization approach indicates the agency’s intent to continue to move aggressively on chemicals. The risk assessments on the first seven chemicals will be released later this year and will provide important insights into the actions the agency intends to take toward both identifying potential risks associated with the chemicals and addressing those risks. The first risk assessments also will lay the groundwork for the agency’s efforts with regard to the next 18 chemicals, as well the remaining chemicals on the priority list.
US EPA has stated that if its risk assessment indicates a significant risk, it will evaluate and pursue appropriate risk reduction actions. If an assessment indicates no significant risk, US EPA will conclude its current work on that chemical. How the agency determines what constitutes a significant risk, as well as determines what, if any, risk management actions may be needed, will be critical.