Cal/OSHA issued an advisory to employers on Tuesday that they must protect their workers if working conditions include exposure to wildfire smoke.

The advisory from the state agency included a list of places where masks are available, including locations in Thousand Oaks, Simi Valley, Camarillo, Moorpark, Santa Paula and Fillmore.

According to Cal/OSHA, officially known as the state’s Department of Industrial Relations' Division of Occupational Safety and Health, when outdoor workers are exposed to air quality that is designated Unhealthy, Very Unhealthy or Hazardous by local air quality management districts, employers are required to provide filtering respirators such as masks.

Additional information for employers and workers on working safely in heavy smoke caused by the wildfires is available at the agency’s website.

The Thomas Fire has burned in Ventura and Santa Barbara counties for more than two weeks. An update on Tuesday afternoon stated the fire had consumed 271,500 acres and was 50 percent contained.