Problem: For many chemicals, the ACGIH TLVs and NIOSH RELs are much more restrictive than existing OSHA PELs. The differences are typically based on the use of more recent scientific data. State your case as to whether employers should use the most restrictive of the PELs, RELs or TLVs, or if the employer should only have to use the legally enforceable PELs. Support your choice.