OSHA Directives and Letters of Interpretation are important instruments through which OSHA clarifies queries and clarifications. These queries and clarifications can be about any aspect of OSHA relating to employers, employees, unions or associations or organizations. These can be raised at any point of time in the year, and OSHA makes it a point to reply to these entities with the requisite clarifications.
This process is what is called OSHA Letters of Interpretation. OSHA Letters of Interpretation are a kind of FAQ set, which are posted on the OSHA website for employers or other concerned parties to take note of. Most queries answer the exact question raised, and these may serve as a guide to people facing a similar situation.
OSHA Letters of Interpretation can be about any area of OSHA, such as all aspects of inspections, consultation with employees or complaints by them, citations, penalties, employers or employees contestation of penalties with the Review Commission, and related ones.
The important point to note is that OSHA Letters of Interpretation are the result or product of the interpretation of an individual officer to whom the query is directed, of a particular situation. This is not to be taken as a reason to fudge with OSHA implementation by the entity which raised the query.
The easiest way of accessing OSHA Letters of Interpretation is to visit the OSHA website, and click on the particular standard on which information is being sought. There, visit the hyperlinks - if there are any - and locate each paragraph of that section, which is under different headings such as Standard number followed by sub category, i.e., 1904. 31(b) (4). This has complete detail of the Standard. It is easy to interpret how this fits into a particularly situation. This link also offers some more explanation of that particular standard.
OSHA Directives, on the other hand, are directives that are aimed at facilitating a better understanding of the OSHA requirements that apply to the concerned entities individually. OSHA Directives are further classified under Compliance Directives (CPL's) and Standard Directives (STD's). These two are OSHA Directives documents that offer instructions to compliance officers on how they need to go ahead with inspecting employer compliance keeping the relevant OSHA standards in mind. They could also be about clarification of how to ensure that entities comply with a particular OSHA standard.