Sick kitchens: Gas exposes commercial chefs to dangerous levels of air pollution, study finds

Gas is not only making commercial kitchens hotter than they need to be, but they’re also cooking up ingredients that can make chefs and their staff very sick. 

A new study out of the US compared three fully electric commercial kitchens with 24 gas-using ones in California, Pennsylvania, and New York.

What it found in the gas kitchens was air pollution up to 10 times higher than US and international guidelines. 

The study, led by Yannai Kashtan from PSE Healthy Energy in California, measured nitrogen dioxide (NO2), carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), benzene, and temperature at five locations in each kitchen.

Even though the study was small and the authors admit that the sample locations in kitchens could over- or underestimate staff exposure, the findings suggest people working with gas in commercial kitchens are regularly put at risk from air pollution and heat exposure.

During working hours in four kitchens, the nitrogen dioxide levels were dangerously high, reaching a maximum of up to 1000 parts per billion by volume (PPBV) at some points.

Image: Environmental Research journal

The maximum exposure limit over an hour, set by the US Environmental Protection Agency (EPA) and World Health Organisation, is 100 PPBV.

In 17 of the 24 gas-using kitchens, nitrogen dioxide measurements taken next to ventilation hoods and in other parts of the kitchen still exceeded those levels.

Furthermore, staff in the gas-using kitchens returned the next day to an already-polluted space. 

Without ventilation hoods on, lit pilot lights and gas leakage from valves overnight creates a baseline level of air pollution that electric kitchens simply don’t have.

Image: Environmental Research journal

“We documented roughly 170 cumulative hours at worker-relevant locations in kitchens with gas- or propane-fired appliances,” the authors wrote in a letter published in the Environmental Research  journal.  

“This represents four full work weeks of exposure. For workers employed year-round, such exceedances likely recur across months and years. 

“In contrast, fully electric kitchens had consistently low concentrations of combustion-based pollutants and consistently lower peak temperatures across comparable exposure zones.

“In practical terms, it is the fuel choice, not the act of cooking itself, that drives the exposure to gas-phase pollutants documented in this study.”

Nitrogen dioxide can trigger asthma and chronic lung conditions. Benzene is linked to a range of cancers and this risk is cumulative – the more exposure, the higher the risk. 

The study found that carbon monoxide and benzene concentrations did occasionally exceed health benchmarks during work hours, but this happened far less frequently than for nitrogen dioxide.

No need to stand the heat

But chefs are gradually relaxing a death grip on their gas-fired tools, as they discover induction cooktops can achieve the same results.

“If cooking is about control of heat, induction is the ultimate control of heat,” Agrarian Kitchen cofounder Rodney Dunn said in a report by the Global Cooksafe Coalition.

“I was very skeptical, and the more I used it, the more I liked it. That control. The cleanliness of it, and most importantly, no one likes to work in a hot kitchen.”

That view was born out in the recent study, which found the lowest temperatures in electric kitchens. 

Thirteen of the 19 gas kitchens with temperature data recorded maximum temperatures above a US workplace recommendation of 32°C, while 10 exhibited “extreme maximum” temperatures above 38°C. Four kitchens saw temperatures soar above 50°C.

Even chefs who use Chinese ‘wok hei’ techniques to impart a smokey flavour are coming around to induction. 

Lee Ho Fook owner Victor Liong and Ho Jiak owner Junda Khoo told the Global Cooksafe Coalition that not only is wok hei “almost impossible” to achieve on a home hob, but induction is more powerful than gas for achieving the same ends. 

Gas industry still fighting

The slow evolution from gas to electric in commercial kitchens is the target of a culture war the gas industry is still waging.

Last year, the Australian Gas Infrastructure Group (AGIG), which owns two of Victoria’s three gas networks and several in other states, breached the greenwashing code in advertising with a series of now-deleted claims about the cost and performance of electric cooktops on LinkedIn. 

AGIG is still running regular soft-ball social media posts about gas in homes.

But a concerted campaign from gas lobbyists caused the Victorian government to flinch in 2024, when it left gas cooktops out of the Gas Substitution Roadmap.

The roadmap requires all gas appliances, bar cooktops, to be replaced with efficient electric alternatives at the end of their lives. 

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