Marshall v. Barlow's, 98 S. Ct. 1816, 436 U.S. 307 (1978)
OSHA conducts searches of OSHA regulated businesses to assure compliance with worker health and safety laws
Employer refused entry to an OSHA inspector who did not have a warrant to inspect the business
United States Supreme Court found that merely being subject to Interstate Commerce Clause regulation does not make a business pervasively regulated
OSHA inspector must get an area warrant if refused entry.
No probable cause is necessary
Congress could probably give OSHA the authority