Final answer:
The standard known as the OSH Act, which requires safe working conditions and accident investigations, is identified as PL 91-596. It forms the basis for OSHA to enforce workplace safety laws and regulations.
Step-by-step explanation:
The standard that requires employers to provide safe and healthful working conditions and mandates that accidents be investigated is known as the Occupational Safety and Health Act or OSH Act. The correct answer to the question is PL 91-596, which is the Public Law number associated with the OSH Act. This act provides the legal foundation for the Occupational Safety and Health Administration (OSHA) to issue regulations and enforce standards ensuring the safety and health of workers.
Employers are required to protect their workers from known hazards by implementing safety measures, providing training, and eliminating or reducing risks whenever possible. When specific OSHA standards do not apply to a certain hazard, the General Duty Clause of the OSH Act is cited, which also compels employers to maintain a safe working environment.