Ethanol: The Common Chemical with Catastrophic Potential

When most people think of ethanol, they don’t think of a dangerous chemical compound. After all, ethanol is all around us, present in so many of the everyday items we use without thinking twice. It’s the alcohol in a glass of wine, the active ingredient in the hand sanitizer dispensers mounted on walls in every doctor’s office, hospital, and school. Ethanol is in disinfectant wipes, vanilla extract, mouthwash, and cough syrup. It’s one of the most familiar chemical compounds on Earth, and, in most of our interactions with ethanol, it’s completely harmless.

But the reality is that, in certain contexts, ethanol has the potential to cause catastrophic damage.

In manufacturing plants, pharmaceutical labs, food processing facilities, distilleries, and fuel blending operations, workers handle large volumes of ethanol every single day. Whether it’s during production, in the course of cleaning, or while performing routine maintenance, it’s undeniable: interacting with ethanol at industrial scale puts workers at risk.

What Makes Ethanol So Dangerous at Scale

So, why does the same substance that sits in a hand sanitizer bottle on a receptionist's desk become a serious explosion hazard inside a manufacturing plant? The short answer is volume. While ethanol contains physical and chemical properties that are entirely manageable in small, consumer-sized quantities, those same properties become potentially disastrous as the overall quantity scales up.

Ethanol has a flash point of just 55°F, which is well below normal room temperature. This means that ethanol doesn't need to be heated, pressurized, or mishandled to produce flammable vapors. At typical indoor temperatures, it's already doing it. What’s more, those vapors fill a remarkably wide flammable range. Ethanol's lower explosive limit (LEL) sits at 3.3% and its upper explosive limit (UEL) reaches 19%, giving it a flammable range roughly two and a half times larger than gasoline. At room temperature, the vapor concentration directly above an open container of liquid ethanol already sits at approximately 5.8%—comfortably inside that explosive window.

Invisible, Flammable Vapors That Move

What makes ethanol especially dangerous in workplaces is how ethanol vapors behave once they're in the air. Ethanol vapor is approximately 60% heavier than the surrounding atmosphere, which means it doesn't rise and dissipate the way many workers might assume. Instead, it sinks. It flows along floors or pools in low-lying areas, like pits, trenches, drains, basements, and stairwells. It travels through doorways and corridors into adjacent rooms, far from the initial source.

An ethanol vapor cloud that’s released during a routine tank transfer or after a spill can migrate dozens of feet and reach an ignition source that no one in the immediate area would have thought to consider. Safety standards from entities like the National Institute for Occupational Safety and Health (NIOSH) explicitly warn of the risk of “flashback,” which occurs when a flame travels back along the vapors’ invisible path and ignites the liquid source.

"Invisible" is not an exaggeration. Pure ethanol burns with a faint blue flame that produces virtually no smoke, making it extraordinarily difficult to detect in daylight. In fact, emergency responders are trained to use thermal imaging cameras to locate ethanol fires because there may be no visual indication that anything is burning at all. Workers have walked directly into active ethanol fires without seeing them.

On a consumer scale, these risks are virtually nonexistent. A squirt of hand sanitizer evaporates before its vapors can accumulate; even a splash of ethanol in a laboratory beaker stays well within the capacity of a fume hood. But when industrial operations involve open tanks, drum-to-drum transfers, spills that cover large surface areas, or high-volume cleaning with ethanol-based solvents, this same chemistry plays out on a completely different—and highly dangerous—scale.

Where Ethanol Accidents Actually Happen

It would be easy to assume that ethanol fires and explosions are limited to certain types of workplaces, places like refineries or chemical plants, but OSHA's accident database tells a different story. Ethanol-related incidents have been documented in cosmetics manufacturing, pharmaceutical production, biological research labs, food processing plants, university facilities, solvent recycling operations, and even cannabis extraction operations. Anywhere ethanol is used in large volumes, there’s a risk.

What's more striking than the variety of industries, though, is what the incidents have in common. The vast majority don't happen during normal production. Instead, they tend to occur during routine, non-production activities, like maintenance, cleaning, startup, shutdown, liquid transfers, and construction. These are the moments when production-designed safeguards may not apply, when systems are partially disassembled, when equipment hasn't been verified as empty, and when the usual routines give way to improvisation.

The Pattern in Practice

In 2016, a pipefitter working on the sixth floor of a distillation building at Poet Biorefining in Hudson, South Dakota was removing a vent line during an expansion project. As he detached a nine-foot pipe segment, ethanol spilled out, flowed through grated flooring to the fourth floor, and was ignited by welding operations below. The worker was engulfed in flames and died the following day.

OSHA's investigation found several key failures: the pipe the worker detached had never been verified as ethanol-free; “hot work” and line break permit systems were not implemented, leading to welding occurring in an area where flammable substances could be present; and the company failed to adequately train workers in process safety procedures and hazards. Workers were also not provided with adequate personal protective equipment (PPE), specifically, flame retardant clothing. As a result, both the contractor and facility operator were cited, the contractor for five serious violations and the facility operator for three process safety management violations.

Three years later, in October 2019, two 126,000-gallon ethanol storage tanks exploded at a NuStar Energy facility in Crockett, California. The subsequent 528-page investigation revealed that a measurement device inside one of the tanks lacked proper electrical grounding, a venting safety valve had been disabled years earlier and never replaced, and the tank's floor coating was actually inhibiting the grounding system. The resulting fireball ignited a 15-acre vegetation fire, forced shelter-in-place orders across parts of Contra Costa County, and shut down Interstate 80 in both directions. Damage estimates reached $25 million. Cal/OSHA's fine: $225.00. County supervisors publicly called the disparity "egregious."

In July 2023, two explosions ripped through the Ringneck Energy plant in Onida, South Dakota during a facility restart. The state fire marshal determined that operators had ramped up the restart process too quickly and bypassed a valve interlock, sending high-proof ethanol into a corn slurry tank where it was never supposed to go. Escaped vapors found ignition sources. Walls were blown off every side of the production building. The plant faced an estimated year-long shutdown.

One of the most dramatic cases documented in OSHA's Technical Manual involved a welding contractor cutting into the top of a 50-foot-tall saccharification tank at an ethanol manufacturing facility. The tank held 40,000 gallons of corn mash, and no one had tested the atmosphere inside before work began. Ethanol vapors had accumulated in the headspace. When the welding arc made contact, the resulting explosion launched the entire tank 75 feet into the air, rupturing interconnecting pipes that released an estimated 1,700 gallons of sulfuric acid. The airborne tank landed on a railcar and an ethanol tanker truck, sparking additional fires. The contractor was killed.

Beyond large-scale facility disasters, OSHA's records document a steady stream of smaller but no less devastating incidents: workers burned when ethanol vapors ignited during tank cleaning, flash fires during solvent recycling startups, and explosions during calibration work on drums containing ethanol waste mixtures. In nearly every case, the injury occurred during a task the worker had likely performed many times before. And in nearly every case, the safeguards that might have prevented it were either absent or had been set aside for the sake of convenience or speed.

It's Not Just Industrial Facilities

The danger isn't confined to factories and refineries. During the COVID-19 pandemic, facilities across the country rapidly pivoted to producing alcohol-based hand sanitizer, a product containing anywhere from 60% to 95% ethanol. Distilleries, breweries, and chemical plants that had never manufactured flammable liquids at that volume were suddenly handling them daily, often without the storage infrastructure, ventilation systems, or fire protection that the work demanded.

The consequences came quickly. A chemical plant in Mumbai, India that had just received permission to manufacture hand sanitizer experienced an explosion on its very first day of production, killing two workers and seriously injuring three others. In the United States, a 2022 warehouse fire in Fort Worth, Texas, fueled by stored hand sanitizer, burned for more than a week. An Oklahoma company received a record-setting $6.6 million penalty for improperly storing massive quantities of hand sanitizer that later caught fire.

These weren't industrial failures, and they weren’t random. They were the direct result of scaling up a familiar substance without scaling up the safety systems around it—the same fundamental problem that drives nearly every ethanol accident in almost every other setting.

How Employer Decisions Determine Outcomes

Investigations into ethanol-related incidents routinely trace the root causes back not to individual worker mistakes but to decisions made (or not made) at the employer level, and the pattern is remarkably consistent.

One big problem is that ventilation is often assumed rather than verified. OSHA requires at least six air changes per hour in flammable liquid storage rooms, with exhaust positioned within 12 inches of the floor where heavier-than-air vapors like ethanol accumulate. But many facilities lack continuous air monitoring systems, and a single fan failure or blocked vent can allow dangerous vapor concentrations to build in minutes. Workers in these environments are often expected to rely on their sense of smell to detect a problem, but ethanol's odor threshold sits at roughly 84 parts per million, nearly 400 times below its lower explosive limit. In other words, a worker could be standing in an atmosphere well on its way to becoming explosive and notice nothing more than a faint, familiar smell.

Another major issue occurs when bonding and grounding, the electrical connections required during any transfer of flammable liquids, are treated as optional or, worse, overlooked entirely. A static spark carrying just 0.2 millijoules of energy, far less than a perceptible human shock, is enough to ignite ethanol vapors. The NuStar explosion that caused $25 million in damage and forced an entire county into shelter-in-place traced directly to a single ungrounded measurement device inside a storage tank.

At many facilities, hot work permits and atmospheric testing procedures exist on paper but aren't consistently enforced, particularly during maintenance, construction, and cleaning—exactly the tasks where ethanol exposure risk is highest. At Poet Biorefining, a worker died because no one verified that a pipe was ethanol-free before cutting began. At the saccharification tank, no one tested the atmosphere before a welding arc was struck above 40,000 gallons of corn mash. What's most alarming is that these aren't extreme cases; in workplaces across the U.S. and globally, they're the norm.

Regulations Have Failed to Keep Up

Underpinning all of these employer failures is a regulatory framework that hasn't kept pace. The primary federal standard governing ethanol in workplaces, 29 CFR 1910.106, is based on the 1969 edition of NFPA 30, a standard that’s nearly 60 years old. Ethanol is absent from OSHA's Process Safety Management (PSM) chemical list entirely, meaning bulk ethanol operations face less regulatory scrutiny than facilities handling far less common hazardous materials.

When the most severe penalty a state regulator could levy against NuStar was $225 for an explosion visible from a highway, it becomes clear that compliance alone was never going to be enough. The responsibility to protect workers from ethanol's hazards falls squarely on employers, and the record shows how often that responsibility goes unmet.

Ethanol Injuries Are Preventable, Not Inevitable

When an ethanol fire or explosion injures a worker, it’s often framed as a freak accident: a momentary lapse, an unpredictable chemical reaction, or an isolated case of bad luck. Employers and insurers have every reason to reinforce that narrative, but the record tells a very different story.

Ethanol-related workplace injuries trace back, consistently and overwhelmingly, to higher-up decisions, decisions about how ethanol is stored, where it's used, and whether ventilation systems are designed and maintained. The choice to use or not use monitoring equipment, to control or not control ignition sources, to actually enforce procedures for non-routine work, these are all choices that have significant consequences.

Every safeguard that could prevent an ethanol fire or explosion—proper ventilation, bonding and grounding, atmospheric monitoring, hot work permitting, or management of change protocols—is the employer's responsibility to implement and maintain. Workers should never have to rely on smelling vapors or spotting a nearly invisible flame to protect themselves from a hazard their employer had every ability and obligation to control.

At Arnold & Itkin, we have seen firsthand how employers who ignore safety standards, cut corners, and dismiss employee concerns set the stage for catastrophic, life-changing tragedies. Our firm is committed to holding these companies accountable and seeking justice on behalf of workers and their families. No matter what.