As millions of workers gaped at the thick haze enveloping the Northeast US this week, they faced yet another remote work conundrum: Should they commute in a smoky haze to a well-ventilated office or is it safer to stay home?

Employers are taking different tacts. Some human-resources chiefs are touting their offices’ upgraded ventilation systems and pandemic-era air-filtration devices as a haven for workers. Bosses are ordering pizzas for lunch to keep people from venturing out and distributing masks at the door. Others, like Google, are telling employees to avoid the hazards of commuting and work from home. New Jersey sent all state employees home at 3:30 pm Wednesday, and had a two-hour delayed opening Thursday, according to the state health department.

Outside of California and other smoke prone places, few guidelines exist around protecting workers from the effects of wildfires. The federal Occupational Safety and Health Administration has no indoor air-quality standards, and very few states have any workplace regulations. (New Jersey has one that covers only public employees.) So, once again, private employers are using their discretion on deciding what’s safest for workers during a potential health crisis.

“It’s a complicated problem,” said Anthony Wexler, director of the air quality research center at the University of California, Davis. “Do you want to give medical advice to your employees and have liability here?”

Health officials across the US have warned residents to take precautions after wildfire smoke traveling south from Canada unleashed unhealthy air quality levels. The smoke halted inbound flights to LaGuardia Airport, canceled outdoor school and sports activities and prompted New York City Mayor Eric Adams to tell people to “mask up.”

Air quality in New York City remained at hazardous levels Thursday, and the plume itself covers most of North America. The health warning for most states will last for at least another day. New York state is distributing a million N95 masks Thursday, as officials across the region urged residents to stay inside.

The latest office attendance quandary comes as many employers are revoking lax remote work rules and enforcing strict return to office policies. Just this week Google told workers they would face penalties on their performance reviews if they didn’t come in at least three times a week, the Washington Post reported. That left some employees confused and anxious as the air got increasingly acrid this week. New York City had some of the worst air quality in the world Wednesday, which is a popular day for in-office attendance. For some firms, it is a so-called “anchor day” when all employees must be in.

Those who came into offices with high-quality air filtration systems were “almost surely more protected than they are at home,” where filtration efficacy can vary widely, according to Marshall Burke, an associate professor in the Doerr School of Sustainability at Stanford University.

HVAC systems are graded on the so-called MERV scale, short for “minimum efficiency reporting value.” The higher the rating, the better the filter is at trapping tinier airborne particles. A MERV of at least 13 is recommended for commercial buildings, according to the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). During the pandemic, many buildings upgraded to heavy-duty systems with MERVs of 13, while others added portable air purifiers equipped with HEPA filters, which are also effective.

Workplace safety experts disagreed on the best course of action.

“At offices with good filtration, I would tell people to come into work,” said Burke, whose research has examined what local governments should tell the public about how to protect themselves from smoke during a wildfire.

Others advised not pushing one way or another. “Allow your employees to work where the air is safest for them,” Steph Little, a senior consultant at Canadian HR firm Bright + Early, wrote in a LinkedIn post. “In some cases this might be the office. In others, this may be home.”

Some said commuting would do more harm than staying home, though. “Would you expect your workers to wade through polluted floodwaters because your building is dry? If not, why ask them to wade through heavily polluted air,” said Eric McNulty, associate director of the National Preparedness Leadership Initiative at Harvard University.

Outdoor workers face greater risks and typically have fewer options. The New York State Department of Labor’s Division of Worker Protection advised employers to limit farming and agriculture, construction, landscaping and highway maintenance.

Madeleine Catzaras of Aon, who works with employers on strategies to address the health-related needs of their workforce, said employers should provide such workers the option to work from home. If that’s not possible, protective equipment like masks are a must, and if that’s not available, they should consider giving them time off.

“If you are vulnerable and have to be outside, it’s a great day to take paid time off,” Burke said.

--With assistance from Jo Constantz.