Companies in California may be tasked with developing policies and communication plans for protecting workers from wildfire smoke if a proposed emergency regulation takes effect, but the scope of the proposal remains unclear.

The Division of Occupational Safety and Health of California released its proposed Protection from Wildfire Smoke regulation, which outlines minimum air quality standards, communications and training requirements, and engineering and administrative controls for dealing with wildfire smoke. Based on the U.S. Environmental Protection Agency’s air quality index, which rates air quality from 0 to 500, unhealthy air from wildfire smoke is anything rated greater than 150 on the air quality index for particulate matter less than 2.5 micrometers in diameter.

“This is an environmental problem that potentially impacts indoor air quality, and it’s not an easy solution to fix,” said Chris Spicer, managing director of industrial hygiene at Pennington, New Jersey-based WCD Group LLC, a subsidiary of Gallagher Basset Services Inc.

According to Cal/OSHA, wildfire smoke contains chemicals, gasses and fine particles that, if breathed in, can reduce lung function, worsen asthma and other existing heart and lung conditions, and cause coughing, wheezing and difficulty breathing. The health effects of wildfires can be experienced as far as 300 miles from the smoke-impacted area, according to a November 2018 study conducted by researchers at Virginia Polytechnic Institute and State University in Blacksburg, Virginia,

Experts believe California will see another significant wildfire season, and Gov. Gavin Newsom issued a state of emergency in late March that stated tree die-off in the state could create an “extremely dangerous fire risk” and allocated $550 million toward wildfire prevention strategies.

The proposed regulation, however, does not make clear what workplaces will be required to comply with the regulation if it takes effect, said Mr. Spicer. The document states that workplaces in enclosed buildings where air is filtered by a mechanical system are exempt, and that an employer may be exempt if it can demonstrate that its air meets certain standards, but it is silent on the required filtration that would be necessary to obtain the exemption or how building owners demonstrate their compliance with the air quality standard, he said.

Gabrielle Sigel, partner and co-chair of Jenner & Block LLP’s environmental and workplace health and safety law practice group, agrees that there is “uncertainty” in the language regarding which workplace and operations are actually exempt.

“Hopefully some of these issues will be addressed (in the comment period),” she said.

In a Cal/OSHA board staff review of the proposed regulation published in late February, staff found “inherent flaws” in the regulations, noting that the air quality index was “not intended to be an indicator for triggering mandatory occupational health controls” and that air pollution levels “measured at a particular monitoring site are not necessarily representative of the worksite.”

The staff review also noted that in the event of a wildfire, “it may not be feasible to follow all the requirements of the respiratory protection program such as medical evaluation and respiratory fit testing of all of the employees who will wear a respirator.”

Mr. Spicer also shared this concern, noting that once respirators are used, it presumably triggers enforcement of U.S. Occupational Safety and Health Administration’s respiratory protection standard, which requires, among other things, medical examinations, fit testing, formal training and written respirator protection programs.

The requirements for employers to check air quality conditions also presents a challenge, said Anthony Bahno, senior vice president in Marsh Risk Consulting’s workforce strategies practice in San Francisco. For instance, employers with multiple locations and crews working in a wide geographic area may need to have someone tasked with making those air quality checks for all work areas during wildfire season, he said.

Although it is uncertain whether the regulation will take effect or what it will look like in its final form, Trever Neuroth, an associate in the Washington D.C. office of Jackson Lewis P.C., suggests that employers communicate with employees about the air quality risks and make sure workers feel empowered to bring up any concerns they have regarding the air quality in the workplace.

“Make sure employees are aware that there is a policy in place, what supervisors and upper-level management are going to do to inform employees of air quality hazards … and the protective measures that they provide,” he said. “It needs to be an interactive process between the employer and the employees.”

Explain to employees the potential impact of wildfires on the workplace air quality and some of the measures that may have been taken to mitigate this exposure, such as installing improved air filtration devices, said Michelle Copeland, president of Occupational Safety Resource Inc. in Gig Harbor, Washington, which provides industrial hygiene consulting for companies nationwide.

Ordering N95 face masks is something else employers in wildfire regions may consider, said Ms. Sigel. The masks retail for about $12 and according to the EPA, filter out 95% of small airborne particles.

“Make sure they’re kept in a clean location so they can be used,” she said. “It won’t hurt to have them.”

The comment period for the proposed regulation closed Friday, but Cal/OSHA has scheduled a public advisory meeting on the proposed emergency regulation May 8 in Oakland, California. After the hearing, the emergency regulation could take effect as soon as mid-May, said Mr. Neuroth.