The scariest sci-fi movie on Netflix mirrors a real-life threat

Fifteen years ago, the film adaptation of the Stephen King novel, The Mist, came out in theaters.

Audiences were floored by the film’s shocking ending, but perhaps less spoken about is what came before: the creeping dread and horror induced by the pervasive mist enshrouding a small, tight-knit town in Maine.

While deadly supernatural elements lurk in the movie’s mist, the idea of mist — or its close relative, fog ‚ harming or even killing humans is no mere fantasy. It’s actually real. Intrigued? Allow us to explain. Spoilers ahead for The Mist.

Reel Science is an Inverse series that reveals the real (and fake) science behind your favorite movies and TV.

When mist turns deadly

In The Mist, people begin disappearing into a thick and heavy mist, which has suddenly engulfed the town of Bridgton, Maine. Survivors huddle together in a grocery store, and it quickly becomes clear that supernatural monsters are killing the townspeople.

As it turns out, there is a deadly mist that exists in real-life — and if it weren’t for strict environmental regulations, you might be breathing it in right now. It’s an overlooked air pollutant called sulfuric acid mist, and it typically emits from industrial factories such as coal-fired power plants. It forms when a colorless substance (sulfur trioxide) in a plant’s exhaust gas mixes with water vapor in the atmosphere, creating a mist.

In some plants, exhaust gas is supposed to be sent up through a device called a “scrubber” to remove the sulfuric acid, but if the company fails to invest in such equipment, the sulfuric acid mist can escape into the air, forming a visible blue plume from the smokestack. Other methods — including large filters known as baghouses and particulate control devices called wet electrostatic precipitators — can remove sulfuric acid mist from the exhaust gas.

Sulfuric acid mist is a carcinogen that has documented harmful effects on humans, including an increased risk of larynx and lung cancer in exposed plant workers. According to the Canadian Center for Occupational Health and Safety, inhaling sulfuric acid carries a risk of death and can cause a “life-threatening accumulation of fluid in the lungs.”

Strangely enough, a small town not unlike the one in The Mist was almost wiped off the map due to sulfuric acid mist. The Gavin power plant in Ohio is the seventh-largest emitter of carbon dioxide in the U.S., and just this month, the EPA ordered the plant to stop dumping toxic coal ash.

Yet its worst legacy lives on in the ghost town of Cheshire, Ohio, after the Gavin plant emitted high levels of sulfuric acid and harmed the health of some residents. Following a lawsuit, the American Electric Plant (AEP) — the owner of the Gavin power plant — bought the entire town of Gavin. More than 200 residents chose to sell their homes to AEP and left, turning the community into a ghost town.

But sulfuric acid continues to threaten communities. In 2021, the Louisville Gas & Electric Company, which violated the Clean Air Act by emitting significant sulfuric acid mist into the surrounding community, agreed to permanent limits on sulfuric acid emissions.

How fog kills millions

But there are also monsters lurking in everyday mist and fog — not just in Hollywood. (Fog is similar to mist but is denser and lasts longer).

This monstrous fog is called smog, and it occurs when pollutants like nitrogen oxide — commonly found in the exhaust gas of cars and factories — enter the atmosphere. Sunlight reacts with these chemicals, forming smog, which blankets cities with high levels of air pollution, like Los Angeles and Beijing.

Smog contains high levels of air pollutants, including small microscopic particles known as PM2.5, which can damage health over time. Recent research has found that air pollution is responsible for one-in-six deaths worldwide, and it particularly takes a toll on children’s health. Studies have linked fog to increasing air pollution.

Air pollution is a slow killer, gradually harming victims through respiratory disease, but there is one infamous example of mist killing people en masse in a single event: the Great London Smog (which was also depicted in the Netflix TV series, The Crown). In December 1952, a deadly fog of — you guessed it — sulfuric acid descended upon London, blocking out the Sun and killing at least 4,000 people on record, though the actual death toll may be much higher. The smog finally lifted when a cold front moved in, lifting the rotten-smelling fumes.

Scientists recently learned how the London smog became so deadly. It seems that coal-burning factories released sulfur dioxide and nitrogen dioxide chemicals into the air, where they mingled with water vapor in the fog, thereby producing sulfuric acid. The acid fog droplets evaporated, leaving smaller acid particles that blanked the city in a thick, deadly fog.

Can mist save us?

Even though the mist in the Stephen King film leads to the townspeople’s doom by obscuring the deadly monsters hiding in its wake, some governments are strangely betting on mist to save us from air pollution.

Since 2015, China’s government has been deploying “mist cannons” — also known as “magic smog cleaners” to combat seasonal air pollution in Beijing and other cities. The machines shoot pressurized water into the air, which becomes a fine mist that absorbs smog, according to India Times.

“The cannons work by spraying nebulized water droplets to trap dust particles in the air,” reported China Dialogue in 2016.

But, much like in the movie, the mist from the cannons eventually disappears, and air pollution will resume again without a long-term plan to curb the source of pollution: industrial fossil fuel emissions. Behind the mist cannons lurks a far deadlier threat than any supernatural creature Stephen King could conjure: climate change.

The Mist is streaming now on Netflix.