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(January/February 2007)

By Gary Mauer

This is the middle of winter; if it ever gets freezing cold where you live and work, this is the middle of your alcohol season. And it's always alcohol season if you're one of the many who use alcohol as a solvent year round. This article can help you understand the hazards involved with alcohol, as well.


There are 3 types of types of alcohol suitable for use as window cleaning antifreeze. From a safety point of view, it's important to think of them as alcohol products, rather than concentrates or cleaning solutions, so this article refers to them as methyl alcohol, isopropyl alcohol and ethyl alcohol.

Methyl alcohol is also known as methanol, methyl hydrate wood alcohol or wood spirits. (The active ingredient in windshield washer premix.)

Isopropyl alcohol is also known as isopropanol, IPA, or rubbing alcohol

Ethyl alcohol is also known as ethanol, or grain alcohol (The primary ingredient in denatured alcohol.)

Some window cleaners don't even realize they are working with an alcohol product because they - or perhaps their employers - aren't reading product labels thoroughly, much less the MSDS (Material Safety Data Sheet) that every chemical maker is required to make available.

Three kinds of alcohol are most commonly used; methyl alcohol, isopropyl alcohol and denatured ethyl alcohol. It's important to realize that all of your antifreeze options are based on some type of alcohol, they are all hazardous to some degree, and they are all flammable. The exposure limits for inhalation and skin contact are surprisingly low, and the lists of potential health hazards is alarming.

An MSDS sheet and safety education is a must for any alcohol product used as an antifreeze or a solvent, even a common consumer product like windshield washer premix, which may contain 20 to 50 percent or more methyl alcohol.

In fact, the OSHA directive "Inspection Procedures for the Hazard Communication Standard" uses the example of, "An employee using windshield-wiper fluid on a daily basis to clean windows" to explain how a consumer product would be covered by their Hazard Communication Standard, because, "use of this fluid differs from the intended purpose, and the frequency and duration of exposure is significantly greater than that of a normal consumer."

Based on a comparison of information in MSDS sheets and many other sources, the most common antifreeze - methyl alcohol - is the most dangerous. A careful reading can find several significant differences between the MSDS sheets for methyl alcohol and isopropyl alcohol, notably the number of times words like poison, danger, fatal, death, convulsions, liver damage, etc. are used. There are also significant differences in a health rating of 3-Severe(Poison) and 2-Moderate.

Isopropyl alcohol is widely considered to be safer than methyl alcohol, but don't let your safety guard down. Common rubbing alcohol is 70% to 90% isopropyl alcohol. You might think isopropyl alcohol was safe for your skin, but a quick look at the label warns you, among other things, not to apply rubbing alcohol to large areas of the body, not to use it for more than a week unless directed by a doctor, and that fumes may be harmful. Study the MSDS and take the precautions seriously.

Denatured alcohol is common ethyl alcohol - the kind of alcohol you can drink - that has had something poisonous or foul tasting added to make it undrinkable. (And thus, not subject to liquor taxes.) Denatured alcohol is often used year round a cleaning solvent, and could be used as an antifreeze, if you can find a safe formula. Unfortunately, there are many formulas for "denaturing" ethyl alcohol, including the addition of up to 10% methyl alcohol, isopropyl alcohol, naphtha or methyl isobutyl ketone. Depending on the formula for a particular product, denatured alcohol could actually be more hazardous to a window cleaner than methyl alcohol or isopropyl alcohol. Study the MSDS for a particular product to see what you're getting into.

Make yourself aware of not only hazards such as flammability, inhalation, skin contact and ingestion, but also safety measures for handling and using alcohol. Acknowledging the need for adequate ventilation and rubber gloves for skin protection are just a start. Heavy winter clothing, for instance may keep minor splashes away from the skin, but alcohol soaked clothing is hazardous any time of year, and many window cleaners don’t even realize they need to change clothing that gets soaked with alcohol. Many window cleaners don’t realize that methyl alcohol is considered to be difficult to wash away from skin, and that merely wiping it off can be unsafe.

Ingestion is obviously the least likely hazard to a window cleaner, but don't overlook the usual precautions about using only clearly marked containers. A sports bottle or a jug that originally contained water looks just as drinkable when it's full of methyl alcohol. Mark everything, and follow every precaution you can learn about.

It is very tempting to overuse something as cheap as methyl alcohol - and it's amazing how you can skimp when you're running low, or when the stuff seems too expensive or dangerous to use liberally.

Isopropyl alcohol is the safer alternative, but it costs more than methyl alcohol, and is not as readily available bulk quantities. One way to make a safer product seem more affordable is to reduce your overall use of alcohol. With that in mind, here are some thoughts on ways to skimp on antifreeze.

Do you really need alcohol just because the air temperature is a bit below freezing? You can get away without adding any alcohol if you're cleaning single pane windows at 20 degrees Fahrenheit - or cleaning double pane windows at 26 degrees Fahrenheit or warmer. That's because the heat from the building warms the glass. You can even go a little lower still if you can stay out of the shade - not so low on a windy day.

One way to cut back on overall use of alcohol is to use smaller batches of solution. Try using a long bucket, like those made by Ettore, Pulex, Unger, and Sorbo. They allow you to dunk your scrub wand lengthwise, so the water does not need to be very deep. You will be able to "tap" the wand lengthwise, into the long bucket instead of dunking one end at a time. So with a long bucket, you can work with a gallon of solution instead of 3. With 2/3 less water in the bucket, you need only 1/3 of the alcohol.

Another way to help conserve alcohol is to use a bottle instead of a bucket. A bottle and holster combo is available from most suppliers, and in a pinch, a common reclosable sport bottle can be used. When doing first floor windows, plant the scrubber on the glass and squeeze the bottle while holding both at arm's length. For pole work, put the on the pole before wetting, so it's held further away.

Using cold water helps save alcohol. Adding alcohol to warm water will cause it to evaporate faster. This will waste alcohol and probably increase your exposure to vapors, because that warm bucket is a very tempting hand or glove warmer.

Alcohol is flammable.

The types of alcohol commonly used as antifreeze have a flash point between 50 and 55 degrees Fahrenheit. Essentially the flash point tells you the temperature at which a mere spark could ignite vapors. At temperatures below the flash point, ignition is still possible under the right circumstances. If a source of heat is introduced, such as a well-aimed cigarette or an electrical short, it can locally raise the temperature above the flashpoint and cause ignition.

Dilution with water won't necessarily prevent ignition. Solutions of more than 26% methyl alcohol are classified as flammable, in part because it will be the vapor, not the liquid itself that burns. Window cleaners who use pure methyl alcohol often end up with much higher concentrations. Bert Goetz, the former owner of Max Wilde Window Cleaning in Winnipeg, said they would routinely use 90% methyl alcohol on the coldest days, and actually did have to deal with a bucket fire on a scaffold caused by a cigarette.

With flash points between 50 and 55 degrees, alcohol is a particularly dangerous product to handle indoors, or to store during the off-season in garages, barns, etc. Outside or detached storage is preferred, and containers may need to grounded to avoid static sparks. Smoking and tool use should not be allowed in storage areas. Any heat source in close proximity can cause an explosion or fire. Consult with your local fire department and your supplier for storage guidelines.

Alcohol products are hazardous, and it is ultimately your responsibility to educate yourself and to comply with recommended safety measures, regulations, and guidelines. There is a lot to learn, so learn everything you can, and work as safely as you know.


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