Process for Evaluating the Toxicological Evidence

Health assessors will use different approaches to evaluate noncancer effects versus cancer effects, but both include evaluating the available toxicological evidence. After we talk about evaluating the evidence, we will summarize the different approaches for evaluating noncancer and then talk about cancer effects.

This process is aimed at evaluating the available evidence — in light of uncertainties — and giving an overview of whether noncancer and cancer health effects are likely or not likely under site-specific exposure conditions. Health assessors will consider various factors in the evaluation, such as the following:

• Quality of the study (note: we know a study used by ATSDR or EPA to develop a health guideline was already determined to be of good quality; here you can assess whether your site-specific exposure conditions and the study design are sufficient for making decisions about harmful health effects)
• Relevance of critical study to site-specific scenario

For information on how examining the evidence fits into the approach for evaluating health effects and see examples using the case study, refer to the next two sections: Evaluate the Evidence: Noncancer and Evaluate the Evidence: Cancer.