OSHA Basics: Letters of Interpretation (LIs)

As part of our OSHA Basics series, in which we explain some basic information about OSHA, we’re turning our attention to OSHA’s letters of interpretation.

If you’ve never heard of a letter of interpretation, they’re worth knowing about.

Or, maybe you’ve heard of them, but have always been a little curious about what they are. If that’s the case with you, we think we can help you out.

Or maybe you’re just curious about how to find OSHA’s letters of interpretations so you can read them yourself. Again, we’ve got you covered.

OSHA Standards and Letters of Interpretation

Before we explain what a letter of interpretation is, it will help to step back and explain what an OSHA standard is.

OSHA Standards

An OSHA Standard is an occupational health and safety rule or regulation (or a set of rules/regulations). OSHA standards occupational safety and health rules for general industry, construction, the maritime industry, agriculture, and recordkeeping. Go to this OSHA website for a complete list of OSHA standards.

The basic idea behind these OSHA standards is that an employer should read the standard relevant to the employer’s workplace, and then follow all the rules and suggestions in the standard to create a safer, healthier workplace.

But because OSHA standards are written for a wide audience, it’s sometimes difficult to understand exactly how to interpret a standard and/or how to apply it in specific circumstances. And that’s where letters of interpretation come in to play.

OSHA Letters of Interpretation

As explained in OSHA Instruction ADM 8-0.3, a letter of interpretation (also called an “LI) is something that:

…provides supplementary guidance that clarifies how to apply to a specific workplace situation a policy or procedure disseminated through the Code of Federal Regulations or the OSHA Directives System. An LI may not interpret the OSHA Act, or establish or expand OSHA policy. LIs may answer questions posed by OSHA, employers, employees, or other parties.

There are at least three interesting things in the explanation above:

  1. LIs are NOT an interpretation of the OSHA act (despite what the name suggests) and they don’t establish or expand OSHA policy
  2. LIs provide supplementary guidance to clarify how to apply a standard in a specific workplace situation
  3. LIs are in the form of answers to a question

Where Can I Find These Letters of Interpretations?

OSHA has created a website that lists all of the letters of interpretations (LIs).

This list is handy because you can click the different tabs at the top to see the LIs listed in order of their publication date (going from way back in 1972 to the present) or see them listed in order of the standard number that they interpret. So that can be pretty handy.

In addition to the lists of LIs mentioned above, if you go to OSHA’s website where they print all of the regulations online, you’ll see that some of the standard numbers are displayed with blue underlines. These blue underlines are web links, and they signify that the standard has one or more letter of interpretation associated with it. See the image below to see that blued underlined numbers in the 1910.23 ladder safety regulation as an example of what we’re talking about.

OSHA Letters of Interpretation Image

If you click one of those blue underlined/hyperlinked numbers, you’ll see a list of LIs that relate to that rule.

For example, if I click the underlined 1910.23(a)(2) link, I see that there are two letters of interpretation. See the example image below.

OSHA Letters of Interpretation Image

Click those underlined/hyperlinked words “Standard Interpretations” and you’ll see the specific interpretations listed, as shown below:

OSHA Ladders Letters of Interpretation Image

And click one of those two links and you’ll see and be able to read the actual letter of interpretation, as shown below.

OSHA Letter of Interpretation Image

And that, in short, is what a letter of interpretation is. Hope that helped!

Conclusion: OSHA Basics and Letters of Interpretation

If you found this “OSHA Basics” article on letters of interpretation helpful, you may also appreciate some of the following articles:

And before you leave, download our free EFFECTIVE SAFETY TRAINING GUIDE, below.


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Jeffrey Dalto

Jeffrey Dalto

Jeffrey Dalto is an Instructional Designer and the Senior Learning & Development Specialist at Convergence Training. He's worked in training/learning & development for 25 years, in safety and safety training for more than 10, is an OSHA Authorized Outreach Trainer for General Industry OSHA 10 and 30, has completed a General Industry Safety and Health Specialist Certificate from the University of Washington/Pacific Northwest OSHA Education Center and an Instructional Design certification from the Association of Talent Development (ATD), and is a member of the committee creating the upcoming ANSI/ASSP Z490.2 national standard on online environmental, health, and safety training. Jeff frequently writes for magazines related to safety, safety training, and training and frequently speaks at conferences on the same issues, including the Washington Governor's Safety and Health Conference, the Oregon Governor's Occupational Safety and Health Conference, the Wisconsin Safety Conference, the MSHA Training Resources Applied to Mining (TRAM) Conference, and others.

4 thoughts on “OSHA Basics: Letters of Interpretation (LIs)

  1. I appreciate this explanation in relatively simple, understandable terms. I have heard the term and had a basic guess of what it meant but I now have a more thorough understanding.

  2. I am trying to understand why the language in 1910.24 (f) 2012 edition was left out of current standard.( (f) Stair treads. All treads shall be reasonably slip-resistant and the nosings shall be of nonslip finish. Welded bar grating treads without nosings are acceptable providing the leading edge can be readily identified by personnel descending the stairway )
    Do I need to write a “Letter of Interpretation” to have this answered?

    1. Thomas/Tom,

      It’s always worth a try, right? I’d suggest writing the question to OSHA and maybe they’ll turn it into a LOI. Or, maybe just asking your local OSHA contact (someone with Fed OSHA if you’re in a Fed OSHA state and/or someone with your local state OSHA plan if that’s your case). Good luck and let us know if you learn something.

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