Gas-Fired Restaurant Kitchens Expose Workers to Dangerous Air Pollution and Extreme Heat: Study – Indian PSU

Restaurant workers in gas- and propane-fired commercial kitchens are routinely exposed to potentially dangerous levels of air pollution and extreme heat, with nearly 70% of kitchens studied exceeding health-based guidelines, according to a new US study.

A new study has found that gas and propane-fired commercial kitchens can expose restaurant workers to unhealthy levels of air pollution and heat, while all-electric kitchens recorded substantially lower pollutant concentrations and cooler working conditions.

Researchers from PSE Healthy Energy, the Stanford Doerr School of Sustainability and New York University Grossman School of Medicine, in collaboration with chef Christopher Galarza, monitored 27 commercial kitchens across California, Pennsylvania and New York. Of these, 24 used natural gas or propane, while three were fully electric.

The researchers measured nitrogen dioxide (NO₂), benzene, carbon monoxide (CO), carbon dioxide (CO₂), methane (CH₄) and air temperature at locations relevant to workers during cooking as well as overnight periods.

The findings showed that ventilation hoods reduced pollution but did not eliminate exposure. During cooking, hourly average NO₂ concentrations outside ventilation hood systems exceeded the US Environmental Protection Agency’s 100 ppbv air standard in 17 of 24 gas kitchens, or roughly 70%.

One kitchen recorded a 15-minute NO₂ average exceeding 1,000 ppbv, above the National Institute for Occupational Safety and Health short-term occupational exposure limit.

Other pollutants also crossed health benchmarks. Carbon monoxide exceeded California’s one-hour exposure guideline in three gas kitchens, while benzene—a known carcinogen—exceeded the state’s one-hour guideline in five kitchens.

None of the all-electric kitchens exceeded any pollutant threshold during cooking hours.

Gas combustion also drives extreme kitchen heat

The study found that the problem was not limited to air pollution. Gas-fired appliances were also associated with significantly higher indoor temperatures.

In 13 of 19 gas kitchens with temperature measurements, temperatures exceeded both California’s indoor heat-illness prevention regulations and OSHA’s proposed 90°F high-heat trigger.

Ten kitchens recorded maximum temperatures above 100°F, while four crossed 122°F.

Importantly, researchers found that extreme indoor heat could persist even when outdoor conditions were relatively mild. On days when outdoor temperatures remained below 75°F, 10 of 13 gas kitchens still exceeded 90°F indoors, indicating that combustion inside the kitchen was a major contributor.

Personal monitoring of one chef during approximately five hours of service recorded an average temperature exposure of 92°F, with a peak of 106°F.

By comparison, the two all-electric kitchens with temperature measurements were among the three coolest kitchens recorded during service.

Pollution continued after cooking stopped

The study also identified a less obvious exposure pathway: gas appliance pilot lights operating overnight.

In 16 of 22 gas or propane kitchens, researchers recorded higher overnight concentrations of NO₂, CO, CO₂, methane and benzene when ventilation was switched off and pilot lights remained lit.

Seven kitchens exceeded the 100 ppbv NO₂ standard during off-work hours, potentially exposing cleaning crews and early-arriving workers even when cooking was not taking place.

Again, none of the all-electric kitchens exceeded any pollutant threshold at any time of day or night.

A major occupational-health concern

The US restaurant and food-service industry employs an estimated 15.7 million workers, including approximately five million people who spend their entire working hours in kitchens.

The researchers say their findings demonstrate that fuel choice and ventilation are important and actionable determinants of indoor air quality and thermal conditions in commercial kitchens.

The study’s central message is stark: ventilation can reduce exposure, but it may not be enough to eliminate pollution and heat generated by gas combustion. The consistently lower pollutant levels and cooler temperatures recorded in all-electric kitchens point to electrification as a potentially important workplace-health intervention.

For millions of kitchen workers, the issue is therefore not simply what is being cooked—but what fuel is being burned around them while they work.

The writer of this article is Dr. Seema Javed, an environmentalist & a communications professional in the field of climate and energy