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Why do federal chemical risk assessments need a ‘reality check’? Dr. Michael Honeycutt explains

The federal government manages several programs that are charged with assessing the risk of potential adverse effects of exposures to chemicals. There has been much discussion about the scientific integrity of these programs and their ability to deliver timely and credible results to help guide decision makers.

An upcoming panel at the Society for Risk Analysis annual meeting next week will take a close look at efforts to improve one of the more important programs managed by EPA – the Integrated Risk Information System (IRIS), which contains information on assessments of more than 550 chemical substances.

One of the panelists, Dr. Michael Honeycutt, manages the Toxicology Division of the Texas Commission on Environmental Quality (TCEQ) and is responsible for making sure his agency makes scientifically sound decisions when developing environmental regulations and policy. He explains in the following Q&A why IRIS is so important to helping him protect public health in his state and what needs to be done to fix the program.

  1. What’s the biggest health risk that you’re currently trying to manage in your state?

The biggest environmental health risk Texas is currently trying to manage is ensuring an adequate and safe water supply. Texas has endured record-breaking drought for the past several years, causing reservoirs to shrink nearly to their riverbeds and some ground water wells to go dry. A growing population and increased demand for water for agricultural and industrial uses has compounded the issue. Water scarcity has led and will lead to consideration of water sources that in past years were not used. Consequently, issues like the drinking water standards for naturally-occurring metals like arsenic is a big deal.

  1. Why are federal chemical risk assessments so important to state regulators?

Large states like Texas and California often have the resources to do their own assessments. Speaking for Texas, we prefer to use federal assessments when possible in order to use our resources for other issues. Using federal assessment also helps avoid disagreements between TCEQ and EPA which, in turn, bolsters public trust of our actions. The problem arises when federal assessments are unrealistically conservative, leading to overstating environmental risks, and potentially to misprioritization of resources.

  1. Is the government providing you with the information you need to protect public health?

In general, I don’t think the government lacks for information, but I think they oftentimes don’t do a good job of integrating different types of information. In regard to IRIS and the NAAQS (National Ambient Air Quality Standards), I think the federal government doesn’t integrate epidemiological, toxicological, clinical, mechanistic, analytical, and other types of data to develop sound assessments. They often rely heavily on one line of reasoning, ignoring other contradictory lines. Ignoring contradictory lines of reasoning leads to overly-conservative risk assessments. Formaldehyde is a great example of this.

  1. What more needs to be done to improve the quality of chemical risk assessments?

Chemical risk assessments can be improved by bringing stakeholders into the process earlier. EPA seems hesitant to change their minds once they make them up. Getting different viewpoints early can avoid perceived conflicts between EPA and other stakeholders, plus lead to more scientifically-robust assessments. Toxicity values should undergo a “reality check” to make sure they make sense. Assessments of chemicals that are naturally made within the human body (endogenous chemicals) illustrate this point. Developing a toxicity value that says normal levels of an endogenous chemical are dangerously high is ridiculous and causes EPA to lose credibility. If they can’t get it right on something as obvious as endogenous chemicals, what about the other chemicals that aren’t so obvious?

  1. What’s the key takeaway you want people to remember from your presentation?

Scientists in the IRIS program, and in other EPA programs, should not operate in a vacuum. They should listen to other scientists, do “reality checks”, and integrate all lines of evidence in their assessments. EPA IRIS officials will often say that they just do the risk assessments and it’s up to others to make risk management decisions. However, a bad risk assessment can paint a risk manager into a corner and force them to make a bad risk management decision. Though it may seem counter-intuitive, an overly-conservative risk assessment is a bad risk assessment since it leads to bad policy and/or regulatory decisions.

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