; (4) wildfire smoke often persists for extended periods of time and can travel hundreds of miles; and (5) wildfire smoke inhalation is harmful to human health, particularly for vulnerable populations, including outdoor workers. 3. Occupational safety and health standard to protect farmworkers from wildfire smoke (a) Definitions In this section: (1) Agricultural operation employer The term agricultural operation employer means an employer, as defined in section 3 of the Occupational Safety and Health Act of 1970 ( 29 U.S.C. 652 ), engaged in farming or agricultural operation. (2) Farmworker The term farmworker means an employee, as defined in section 3 of the Occupational Safety and Health Act of 1970 ( 29 U.S.C. 652 ), engaged in farming or other agricultural work for an agricultural operation employer. (3) Secretary The term Secretary means the Secretary of Labor. (4) Uniform air quality index The term uniform air quality index means the PM–2.5 category of the uniform air quality index for the air quality monitoring system required under section 319(a) of the Clean Air Act ( 42 U.S.C. 7619(a) ). (b) Initial occupational safety and health standard (1) In general During the period beginning on the date of enactment of this Act and ending on the date of the promulgation of the occupational safety and health standard under subsection (c), the Secretary shall deem the initial standard to protect farmworkers from wildfire smoke described in paragraph (2) to be an occupational safety and health standard under section 6 of the Occupational Safety and Health Act of 1970 ( 29 U.S.C. 655 ). (2) Contents of initial standard The initial standard described in this subsection shall require that an agricultural operation employer— (A) provide farmworkers with appropriate equipment to protect from wildfire smoke when air quality at the workplace reaches a level of 151 or greater, as determined by the uniform air quality index