States must obtain express permission from the Secretary of Labor to promulgate their own laws regulating any area directly covered by OSHA regulation. States are free to regulate any area not covered by federal OSHA regulations. Federal approval of a state OSHA plan has been effected in two-thirds of states as of 2002. The following states have substituted approved state OSH plans for the federal OSHA plan:
- ALASKA
- ARIZONA
- CALIFORNIA
- CONNECTICUT
- HAWAII
- NDIANA
- IOWA
- KENTUCKY
- MARYLAND
- MICHIGAN
- MINNESOTA
- NEVADA
- NEW JERSEY
- NEW MEXICO
- NEW YORK
- NORTH CAROLINA
- OREGON
- SOUTH CAROLINA
- TENNESSEE
- UTAH
- VERMONT
- VIRGINIA
- WASHINGTON
- WYOMING