One gallon of used motor oil seems harmless enough. It’s hard to be a mechanic without getting it on your hands, your tools, your clothes. Generally, there’s no noticeable damage-at least none that a good scrubbing or laundry day won’t remedy. So what’s all the fuss about the dangers of used motor oil?

The fact is that just one gallon of waste oil can render a million gallons of fresh water undrinkable. In addition, if oil finds its way into a pond or lake, it forms a film on the surface that blocks sunlight and prevents oxygen from entering the water. The result is reduced animal and plant life, and maybe contaminated fish you may eventually eat.

The politically correct term for waste oil is now used oil. The official EPA definition for used oil is “any oil that has been refined from crude oil, or any synthetic oil, that has been used and as a result of such use is contaminated by physical or chemical impurities.” It’s generally the oil you drain out during LOF service or the transmission fluid you dump when replacing a transmission filter. But it also includes power steering fluid and gear oil-just about any oil a service station, repair shop or quick-lube shop might discard. When you deal with used oil, you automatically become a used-oil generator.

What Contaminates Oil?

As efficient as modern engines are, the heat they generate still has a deleterious effect on motor oil. Heat causes a breakdown of additives and other key properties of oil. This breakdown creates acids and other contaminants such as dirt, dust and even rust, which make their way into the crankcase, along with small amounts of water and antifreeze. Add to this exhaust gases that leak past piston rings and you have contaminated oil that contains quantities of cadmium, aluminum, lead, steel, iron and chromium, along with scary-sounding arsenic and benzopyrene-real nasty stuff that you wouldn’t want in your drinking water or in the fish you eat.

While used motor oil is not generally considered hazardous waste, it must be disposed of properly. However, if it does get mixed with a hazardous material, it then may be considered hazardous waste. In that case, some serious and costly regulations about handling the stuff kick in.

There’s no doubt that some unenlightened repair shop owners still dump their waste oil in the lot behind the shop or down the sewer, but the vast majority seem to be following safe disposal guidelines. Do-it-yourselfers, who as a group are difficult to regulate, are probably the biggest offenders. According to estimates from the EPA, 142 million gallons of used oil generated by DIYers are disposed of improperly, despite regulations that require service stations, repair shops, quick-lubes and retailers to accept used oil from anyone, even if they bought the oil elsewhere. Remember the damage we mentioned only one gallon of improperly disposed of used oil can do? Imagine the potential damage 142 million gallons can do when it’s dumped indiscriminately.

Storing Used Oil

In the past, it was quite common for used-oil generators to stock up on the stuff, then sell it to people in rural counties who would in turn spray it on roads to control dust. But an understanding of the damage contaminated oil can do has led to federal regulations that pertain to the storage and disposal of used oil. No matter where it eventually ends up, you need to store used oil properly before it turns into a problem that could become very costly. There are also limits as to how much you can store legally.

It’s important to know the rules of used-oil storage in order to prevent spills and contamination that could come back to haunt you long after the stuff has been disposed of. It’s the job of government agencies at all levels to enforce the terms of the RCRA. Violations of those rules in the handling of used oil can result in heavy fines and hold up or void the sale of property when the buyer or the bank determines there may be potentially costly ground contamination. It’s not unusual for contamination problems to take years to be resolved and cost hundreds of thousands of dollars in legal fees and cleanup costs before the violations are finally cleared up. In the meantime, potential buyers often lose interest and look elsewhere. A shop owner hoping to retire on the proceeds of the sale of his shop might be well into old age before all these problems are resolved.

Getting Rid of the Oil

Essentially, there are two things you can do with the used oil you generate. You can have it picked up by a recycling company or you can burn it on-site. Recyclers used to have to pay a shop a few cents per gallon for the used oil it picked up. Now, however, shops pay recyclers to pick up and legally dispose of their waste oil. It’s safer to deal only with a major recycler whose reputation has been well-established, which will assure you that your used oil will be handled according to regulations.

But the EPA doesn’t let you off the hook simply because you get rid of your used oil in a proper manner. It essentially remains your used oil, and you’re responsible for how it’s transported and recycled. If you run afoul of the regs on the state or federal level, the EPA can ask you to produce bills for the oil you bought. Once they know how much you bought, they look for how much you disposed of legally, where it went and how it got out of your shop.

Firms like Safety-Kleen and other legitimate recyclers keep records and provide you with a receipt for every gallon they take off your hands. People in the business like to describe your responsibility for used oil as “cradle to grave.”

One of the nice things about sending your oil to a reputable recycler is that you know it’s going to be put to good use. Recyclers generally distill or boil the used oil to drive out the water, then remove the lighter-end fuels. After that, the oil is put into a vacuum to rid it of heating-type fuels. Hydrogen is then passed through the oil to remove sulfur, nitrogen, chlorine and oxygenated compounds. The process also removes the salts, metals and tarlike substances that might have found their way into the oil during its life in an automobile engine.

Keep in mind that getting rid of these contaminants is why the oil was changed in the first place. So once they’re removed, the oil is essentially the same as it was before it was used. The byproducts of the recycling process are used in the manufacture of asphalt and as industrial fuels. The bulk of the rerefined used oil winds up back lubricating the engines of trains, buses, trucks and passenger cars.

Obviously, properly disposing of used oil is the right thing to do, aside from the risk of heavy fines if you’re caught in violation of the regulations. The EPA has determined that it takes only about one-third the amount of energy to rerefine used oil as it does to refine crude oil. It takes 42 gallons of crude oil to make 2 1/2 quarts of new oil. It takes only one gallon of used oil to make the same 2 1/2 quarts of like-new oil.

Used Oil for Heat

For shop owners in areas where winter means heating the shop, burning waste oil for heat is a good and economical idea. You still have to store the used oil safely until it’s burned, but you avoid the cost of having it trucked away. Unfortunately, not every city approves the use of waste-oil heaters. So before you buy one, check with the local authorities and fire department to be sure they’re approved.

Primitive waste-oil heaters of years ago often had to be tended to like an old coal stove. Filters clogged and grids had to be cleaned sometimes two or three times a day. But all that has changed. Today, waste-oil heaters are incredibly efficient and easy to use.

In recent years, several companies have refined the process of burning used oil for heat into almost an art form. They make everything from floor-mounted units that are no larger than the average mechanic’s toolbox to ceiling-mounted units with heating ducts and vent piping. Models that put out from about 90,000 BTUs all the way up to 320,000 BTUs are available-all from what’s essentially a free supply of fuel in the form of the used motor oil you’d otherwise discard. When you consider what it costs to have the oil removed by a recycler, the idea of burning used oil for heat becomes a very cost-effective endeavor and a downright damned good idea.