OSHA Seeking Public Comments on Weight of Evidence ApproachCurrently, the Occupational Safety & Health Administration (OSHA) uses a document called a Guidance on Data Evaluation for Weight of Evidence Determination as a companion to the 2012 Hazard Communication Standard. The Weight of Evidence plan is intended to help managers and employers determine the proper classification for hazardous chemicals based on all available evidence, and does so by providing a comprehensive plan on how strongly to consider various factors or pieces of evidence.

The plan lets employers understand how to view the various items on standard chemical safety data sheets (SDSs) as parts of an equation whose answer is a proper hazard classification. It does not present any new legal requirements for employers to follow, and instead is intended only as a helpful guide.

In order to make this more helpful, OSHA is opening up the Weight of Evidence guide to public conversation. Reviews can be submitted at this link.

Anyone can leave a comment, but OSHA has provided a list of questions it would like answered. They are as follows:

  1. OSHA’s primary goal in the draft WoE guidance is to provide classifiers with an overview on how to approach a weight of evidence evaluation using the criteria that was adopted under the Hazard Communication Standard (29 CFR 1910.1200).  Has OSHA achieved this goal?
  2. OSHA intended to write this draft guidance in language that is appropriate for, and easily understood by, personnel who would be primarily responsible for the classification process. Has OSHA achieved this objective?
  3. OSHA has also provided guidance on how to use other authoritative bodies that use a weight of evidence or systematic approach. Is this type of guidance helpful? Are there other authoritative bodies that OSHA should reference that that provide weight of evidence evaluations that would be relevant to worker exposures?
  4. To simplify the guidance OSHA has primarily focused on chronic hazards: Carcinogens, germ cell mutagens and reproductive toxicants since these are more complex endpoints and generally need a higher degree of expert judgement to interpret studies.  Did OSHA adequately identify the key considerations for a WoE evaluation of these toxicants?  Was the OSHA discussion of the WoE approach appropriate for this guidance document?
  5. OSHA has provided a section on classification based on a single positive study.  Was this section useful?
  6. OSHA has provided a series of examples to demonstrate the principles discussed in the Weight of Evidence guidance document.  Are these examples helpful? How can they be improved?