Ethyl alcohol is a flammable, toxic, colorless liquid with a sweet, wine-like characteristic odor. It is used as a solvent and a raw material (and is sometimes a by-product) in the production of alcoholic beverages, antifreeze, cleaning chemicals, cosmetics, detergents, dyes, elastomers, explosives, inks, gasohol, lubricants, mouthwash, paints, perfumes, pharmaceuticals, plastics, and many other chemicals and products. Ethyl alcohol is the alcohol present in beer, wine, whiskey, and all other alcoholic beverages.

It exists in grades designated as absolute, completely denatured, industrial, specially denatured (SD), USP, and as various proofs (one-half the proof number equals the percentage of alcohol by volume). Properties and hazards listed for ethyl alcohol are for the pure, anhydrous alcohol (which really is not totally anhydrous, since it contains up to one percent water).


Ethyl alcohol’s flash point is 55°F, its ignition temperature is 685°F, and its flammable range is from 3-3 percent to 18.9 percent. Its specific gravity is 0.79, its molecular weight is 46, and its vapor density is 1.59. It boils at 172.9°F, freezes at — 179°F, and is soluble in water in all proportions. Its chemical formula is C2H.


Ethyl alcohol’s flash point makes it, by definition, a flammable liquid (of course, it’s the vapor produced by the evaporation of the liquid, not the liquid itself, that burns). At 55°F and higher, ethyl alcohol evolves vapors in a quantity sufficient to form an ignitable mixture with the air near the liquid or container. In addition, the term “ignitable mixture” implies that the vapors are in the flammable range, which is the ratio of vapor in air between the upper and lower flammable (explosive) limits. At the flash point or higher, all that is needed to cause an explosion of those vapors is an ignition source within the area where the vapors are in the flammable range, capable of raising the temperature of a small quantity of those vapors to 685°F—ethyl alcohol’s ignition temperature.

The vapor density of 1.59 indicates that those vapors are heavier than air (vapor density of clean, dry air is 1.0), and they hug the ground and flow along low spots in the terrain. The vapors will travel great distances until they find an ignition source (if they’re not interrupted by a strong breeze), whereupon they’ll ignite, with the resulting fire flashing back to the source of the vapors, usually explosively.

Ethyl alcohol burns with a pale blue flame, which might not be visible in bright sunlight. An unsuspecting person may be seriously burned while inadvertently contacting this nearly invisible flame. While it is true that the flame temperature of ethyl alcohol is somewhat lower than some other common flammable liquids such as gasoline, it is still hot enough to burn human tissue, turnout gear, and other exposures. A person burned by such flame exposure will not be able to tell that the flame was lower in temperature than the flames of other common flammable liquids.

Ethyl alcohol’s relatively low ignition temperature means that any common ignition source can provide the energy necessary to ignite ethyl alcohol vapors.

Ethyl alcohol’s toxicity is interpreted by at least one reference to be of a “low order,” while at least one other reference calls it “moderately toxic.” This does not indicate that ethyl alcohol is not poisonous but rather that some quantity of ethyl alcohol may be ingested without fatal effects. However, it is true that consuming a large quantity of ethyl alcohol (in alcoholic beverages) may indeed cause death quite rapidly. Consuming quantities less than that required to produced death but enough to be “felt” by the consumer, on a more or less regular basis, causes damage to specific body organs over a period of time. Humans consume these large quantities in food products and medicines as well as in alcoholic beverages. The specific toxic dose is different for each individual, but regular ingestion of alcohol damages the brain, liver, and other organs. In addition, its addictive powers lead to alcoholism. Each year people die from consuming large quantities of alcoholic beverages and from consuming them with legal medication or illegal drugs.

Denatured alcohol is ethyl alcohol to which some other soluble liquid (such as methyl alcohol, methyl isobutyl ketone, ethyl acetate, heptane, or gasoline) has been added to render the ethyl alcohol unfit for human consumption. The presence of these denaturants drastically increases the toxicity of ethyl alcohol and makes it deadly to humans. There are many deaths reported each year from drinking denatured alcohol.

Ethyl alcohol is considered a stable chemical compound, but it reacts violently with many other materials. Its reaction with sodium and potassium metals and such strong oxidizers as calcium hypochlorite, chlorine oxide, chromic acid, chromic anhydride, hydrogen peroxide, mercuric nitrate, nitric acid, perchloric acid, all metal perchlorates, many permanganates, phosphorous trioxide, potassium t-butoxide, and silver nitrate will be explosive. Explosive or otherwise violent reactions also can occur with acetyl chloride, bromine pentafluoride, chromyl chloride, disulfuryl difluoride, heated aluminum, and sodium hydroxide.

Since most humans can consume ethyl alcohol in some moderation without apparent toxic effects, some people believe they can ingest methyl alcohol, a similar-sounding alcohol, with much the same effect. This is often a deadly error: Methyl alcohol is considerably more toxic. If ingested in less-than-fatal quantities, methyl alcohol attacks the optic nerve and can cause blindness (see Fire Engineering, September 1987).

Ethyl alcohol’s TLV—TWA (threshold limit value—time weighted average) is 1,000 ppm (parts per million of air), which contributes to the widespread belief that it is relatively harmless. At concentrations of 5,000 ppm, eye and nose irritation is possible. Continued inhalation of such high concentrations of vapors can cause dizziness, drowsiness, fatigue, tremors, and narcosis. Repeated contact with the skin can cause drying and defatting action. Animal ingestion tests have shown that ethanol is fatal at 5 grams per kilogram of body weight.


absolute alcohol

absolute ethanol



anhydrous alcohol

cologne spirits

dehydrated alcohol

denatured alcohol


ethanol, 200 proof

ethyl hydrate

ethyl hydroxide


fermentation alcohol


grain alcohol

Jaysol S

methyl carbinol

molasses alcohol




potato alcohol


spirits of wine



In the event of an accidental release of ethyl alcohol (or any hazardous material), notify the proper environmental authorities as soon as possible. Ethyl alcohol is not as damaging to the environment as many other substances, but the proper authorities still must be notified. The first consideration on the scene of a hazardousmaterials incident is the protection of human life, so approach and secure the incident site in a way that prevents the accidental ignition of the flammable vapors, just as you would in any response to the accidental release of any flammable liquid. Approach from upwind (remembering that the direction of the wind could change at some time after you arrive on the scene), and eliminate all ignition sources. Also try to prevent possible ignition sources from entering the danger zone. The danger zone includes any area near the site of the release where vapors may be in concentrations above the lower flammable limit of 3-3 percent.

The major danger to life is the explosive ignition of ethyl alcohol vapors, so exercise care near the spill and near the immediate areas to which the vapors might spread downwind. Ethyl alcohol’s vapor density of 1.59 means that (with no appreciable breeze present) the vapors hug the ground and flow downhill and along low spots. These vapors may accumulate in such low-lying areas or in confined spaces, producing concentrations above the level that causes severe eye and nose irritation and possibly even reaching the lower flammable limit. Always consider evacuation of the area downwind, and clear of unnecessary personnel an area up to one-half mile around the vapor source (depending on the size of the leaking container). Always keep in mind that a fire is usually the second reaction produced by ignition of flammable vapors, the first being an explosion.

Ethanol leaking from a container should be captured and transferred to a secure container if possible. Any equipment used in capture, containment, or other contact with ethyl alcohol or its vapors must not be capable of generating a spark. This includes the use of all tools, pumping equipment, lights, fans, and other electrical equipment, which all must be classified as explosionproof.

If the leaking liquid cannot be captured in a portable tank or some other type of container, it may be captured in a containment pond constructed by pushing dirt, sand, clay, or other absorbent material into a diking configuration around the spill. If the proper equipment is available, a containment pit may be dug to hold the liquid. The size of the pond or pit should be determined by the amount of material involved and potential mitigation techniques available.

One of these mitigation techniques is dilution: Water is added to the ethyl alcohol, increasing its flash point considerably (that is, the temperature of the water-ethyl alcohol solution at which generated vapors are of sufficient quantity to form an ignitable mixture with the air is considerably higher than ambient temperatures). This technique is possible only if the containment pond or pit is large enough to contain the resulting added volume. The flash point of pure (absolute) ethyl alcohol (55°F) can be raised to near 90°F by adding three volumes of water for volume of ethyl alcohol.

The application of alcohol-type foam or aqueous film-forming foam (AFFF) to the surface of the liquid slows down the evolution of vapors. The foam layer may have to be replenished from time to time as it breaks down, and the resulting added volume must be contained, as must all other runoff water or dilute solutions.

Rubber, plastic, or some other impervious material may be used to cover the contained liquid. This is easier to accomplish if a containment pit is used, since the surface area of the pit will probably be smaller than that of a pond. Also, if left uncovered, the evolution of vapors will be less in the case of the pit, since the rate of evaporation is lower with a smaller surface area of the liquid exposed to the atmosphere.

High-pressure water spray or fog may be used to remove the vapors of ethyl alcohol from the air. The ethyl alcohol readily dissolves in the spray or fog, so the runoff water has to be contained.

Once the product has been contained it may be removed by professional cleanup crews. Pumping or suctioning the product from a container or containment pond or pit into secure containers should be done only by properly educated, properly trained, and properly equipped personnel. These personnel and equipment are either provided by or paid for by the manufacturer of the spilled product, the shipper, or the buyer. Firefighters and most other emergency response personnel should not be involved in either salvage or cleanup operations.

Once the product is in secure containers, any remaining liquid may be absorbed by using clay, cement powder, fly ash, sand, soil, commercial products, or any other available absorbent material. This resulting sorbent containing ethyl alcohol must be handled just as safely as the original material and must be disposed of in accordance with federal, state, and local regulations. The environmental authorities will then decide how deeply the contamination has occurred and how much soil will have to be similarly removed.

The presence of denaturants (in a case where the released material is not pure) in the ethanol may make the situation slightly more hazardous because of the denaturant’s toxic properties or lower flash point. However, all mitigation techniques will probably remain the same as long as the properties of the denaturant are known to be somewhat similar to the pure product.

The product must not reach a sewer or waterway. Entry into a sewer can spread flammable vapors and the resulting threat of an explosion throughout the city. Warn all sewage treatment facilities immediately.

If the ethyl alcohol enters a stream or other waterway, warn all downstream users of the water immediately. The toxicity of the product and its effect on fish, waterfowl, and other wildlife depend on the amount of the product entering the waterway, the volume of water, and how fast the water is moving. The product will dissolve immediately in the waterway, especially if the water is moving fairly rapidly. If the waterway can be diverted into a low-lying area by a temporary dam, the ethyl alcohol may be removed by aeration techniques. The same techniques can be used if the product enters a pond or lake.

If the waterway is fast-moving, unless the volume of the spilled product is very large, the product will be diluted fairly rapidly and all resulting dangers may be removed. However, this can be determined only by testing the water at different points downstream; such testing should be done by trained personnel supervised by environmental authorities. While water treatment plants, if properly and timely warned and properly equipped, may be able to remove the contamination, they should not take the chance. If heavily contaminated water enters an industrial intake and contacts hot equipment, the vapors of the alcohol driven out of solution by the heat process might produce vapors of a sufficient quantity to produce an explosion.


If containers of ethyl alcohol are exposed to flames or radiated heat from a fire, a catastrophic failure of the container is possible: Pressure builds up from the rapid evolution of vapors within the container produced by the absorption of energy from the fire. This catastrophic failure will be marked by a fireball produced by the released vapors as they are ignited, a rocketing container propelled by the released vapors, trailing burning liquid (remember, the liquid doesn’t bum, but it sure looks like it as the vapors evolving from the heated liquid are ignited), a concussive effect from the explosion, and shrapnel from the failed container. This sequence of events is characteristic of other contained flammable liquids; the only difference is the damage done by different volumes of liquid in the containers. Other factors, such as the chemical makeup and volatility of the liquid, will produce some differences, but the devastation from the explosion might not seem that different. The point is that all flammable liquids in containers act the same way under similar conditions.

Therefore, protect containers holding ethyl alcohol from such heat exposure and the resulting pressure rise by cooling with water applied from as far away as possible with unmanned monitors. Safe distances depend on the size of the containers (a minimum of 2,500 feet is a safe distance for railcar tanks). Never get caught between a fire and containers of liquids or gases, whether they are flammable or not.

Extinguish burning ethyl alcohol by applying water spray, fog, or alcoholtype foam. You can use carbon dioxide or dry chemical if conditions such as weather, volume of burning liquid, and amount of extinguisher present are right. Follow all rules for fighting flammable liquid fires. Watch for reig-



(Chemical Abstract Services)



(Standard Transportation Commodity Code)

4909159 pure material

4909110 ethyl alcohol, anhydrous, denatured with not more than 5 percent gasoline

4909151 ETOH, denatured

4909146 (not identified)


(Registry of Toxic Effects of Chemical Substances)

KQ 6300000


(United Nations/North America)

1170 ethyl alcohol and alcoholic beverages 1986 toxic alcohol, n.o.s.


(Chemical Hazard Response Information System)



(U.S. Department of Transportation) flammable liquid

NFPA 704 0-3-0


(International Maritime Organization)

3-2 or 3 3, flammable liquid nition of vapors caused by metal heated by the fire or the sudden appearances of other ignition sources.


For inhalation, remove the victim to fresh air. If the victim has stopped breathing or breathing has become difficult, administer artificial respiration (mouth-to-mouth resuscitation may expose the first-aid provider to the material in the victim’s mouth or vomit). Seek medical attention immediately.

For ingestion, if the victim is conscious and less than two hours have elapsed since ingestion, administer large quantities of sodium bicarbonate dissolved in water and induce vomiting. Never try to force an unconscious person to drink anything or vomit. Call for immediate medical attention while making sure the victim is warm and comfortable.

For skin contact, remove all contaminated clothing and wash all affected body areas with large amounts of water. Medical attention is necessary if irritation of the skin persists after washing.

For eye contact, flush the eyes immediately with large amounts of water for 15 minutes, occasionally lifting the eyelids. Provide medical attention immediately.


Choose clothing and protective equipment to prevent contact of the liquid or vapor ethyl alcohol with the eyes, skin, or respiratory system. Select splashproof chemical goggles and a face shield for eye protection and use positive-pressure, self-contained breathing apparatus. Rubber boots, gloves, and aprons and other impervious clothing will offer protection. Manufacturers of total encapsulating suits claim that butyl rubber, nitrile rubber, nitrile-butadiene rubber, polyethylene, polyurethane, and Viton may offer protection.*


Absolute alcohol—alcohol that is free from any other material except for up to one percent water.

Aeration—a process by which air is introduced into a liquid, either by bubbling the air through it or spraying the liquid into the air at normal pressures (may also be called sparging); also called air stripping, which is the spraying of the liquid or gas into the air to remove the contaminant.

Ambient temperature—the temperature of the environment in which any physical or chemical event occurs.

Anhydrous—a chemical term meaning “no water present.”

Denaturant—liquids added to ethanol to make it unfit for human consumption.

Dilution—the addition of water (or other miscible liquid) to reduce the concentration of a hazardous material.

Explosionproof—the covering of all or parts of electrical devices to prevent explosive gases, vapors, dusts, or fumes from reaching an area where an electrical spark or excessive heat may act as an ignition source; any other treatment to prevent explosions.

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