Under 1918.3(a)(1): Which parts of standards incorporated by reference are legally enforceable in Part 1918?
Only the mandatory provisions of an incorporated standard are enforceable; non-mandatory language is not adopted as a standard. See 1918.3(a)(1) which explains that only provisions containing the word "shall" or other mandatory language are adopted as OSHA standards. Employers may still follow non-mandatory guidance, but OSHA enforces only the mandatory text.