The EPA’s draft plan to assess inorganic arsenic risks should take greater advantage of the data that exists on the chemical to reach evidence-based conclusions, says a report from the National Research Council.
While the EPA’s draft plan that describes how the agency will assess the potential health effects of oral exposure to inorganic arsenic includes improved approaches for evaluating evidence and conducting analyses, the report recommends alternative statistical approaches over the EPA’s current default methods for estimating risk.
The EPA’s Integrated Risk Information System (IRIS) assessments identify disease hazards and characterize associations with adverse health outcomes for a wide variety of chemicals. The Research Council produced its report in response to the EPA’s request to review the draft plan for carrying out the IRIS assessment of inorganic arsenic and evaluate critical scientific issues in assessing the potential health effects of oral exposure to the chemical.
Critical Aspects of EPA’s IRIS Assessment of Inorganic Arsenic recommends how these issues could be addressed in an IRIS assessment. A second report will review the draft IRIS assessment, expected to be performed by the EPA in 2014.
The report recommends that EPA develop risk estimates for both cancer and noncancer effects on which there is adequate epidemiologic evidence and then derive risk-specific doses — estimates of the level of exposure associated with a given degree of risk. For those health effects where the data are inadequate for modeling at low levels, extrapolation down to lower levels of exposure will be necessary, it says.
Following the Research Council’s report, US Sen. David Vitter (R-La.), who sits on the Senate’s Environment and Public Works Committee, said the report is an example of “why the EPA’s risk assessment methods are flawed” and the agency’s chemical programs, particularly the Toxic Substance Control Act (TSCA) of 1976, need to be reformed and updated. Vitter says the proposed Chemical Safety Improvement Act — a bipartisan bill to modernize the TSCA introduced by Vitter and the late Sen. Frank Lautenberg (D-NJ) in May — will help the EPA to fix its chemical assessment problems.
In September, the EPA withdrew two draft regulations intended to enhance chemical oversight. One rule would have implemented TSCA Section 5(b)(4) and created a list of “chemicals of concern.” The other rule would have diminished the opportunity for chemical manufacturers to claim as confidential business information — and thus prevent public disclosure — the chemical identity of substances identified in certain health and safety studies submitted to EPA.