29 C.F.R. § 1960.37
(a) For agencies which elect to utilize the committee concept, safety and health committees shall be formed at both the national level and, for agencies with field or regional offices, at appropriate levels within the agency. To realize exemption from unannounced OSHA inspections, an agency must form a committee at the national level and at any establishment or grouping of establishments that is to be exempt, keeping the Secretary advised of the locations and activities where such committees are functioning.
(b) Committees shall have equal representation of management and nonmanagement employees, who shall be members of record.
(2) Nonmanagement members of establishment level committees shall represent all employees of the establishment and shall be determined according to the following rules:
(3) Nonmanagement members of national level committees shall be determined according to the following rules: