Final answer:
A formal lockout procedure in an operating plant facility is typically governed by OSHA standards for Control of Hazardous Energy. It is separate from WARN Act requirements, which mandate a 60-day written notice for plant closings or large layoffs by employers with more than 100 employees.
Step-by-step explanation:
An operating plant facility must have a formal lockout procedure as per regulations that are designed to protect employees from hazardous energy sources on machines and equipment during service and maintenance. While the specific regulation was not cited, this requirement can often fall under the Occupational Safety and Health Administration's (OSHA) standards for Control of Hazardous Energy (lockout/tagout), found in Title 29 Code of Federal Regulations (CFR) Part 1910.147.
It is important to note that having a formal lockout procedure is a separate requirement from providing written notice 60 days before plant closings or large layoffs, which is mandated by the Worker Adjustment and Retraining Notification Act (WARN) for employers with more than 100 employees. The lockout/tagout standard is intended to ensure that machines are properly shut off and not able to be started up again prior to the completion of maintenance or servicing work.