Who dropped a whole truckload of fizzies into the varsity swim meet? Who delivered the medical school cadavers to the alumni dinner? Every Halloween, the trees are filled with underwear. Every spring, the toilets explode.

Dean Wormer
Animal House

Back in 1978 when I first saw the movie Animal House, that line about exploding toilets stuck with me. I assumed the combustion was caused by cherry bombs being tossed in the commodes, but as I recently researched the history of Lowell’s water supply, I learned that city residents were once plagued by exploding toilets. The cause was not fireworks.

The Lowell Gas Light Company was founded in 1849 to produce and convey coal gas throughout the city to illuminate mills, businesses, street lights and homes. Burning coal gas to produce artificial light had been done in England for several decades by that point, and had proved very useful and popular. In the age before electric lights, gas lighting was cleaner, safer, brighter, and easier to use than candles or oil lamps. (For an outstanding book on this topic, check out Brilliant: The Evolution of Artificial Light by Dracut’s Jane Brox).

This gas was not extracted from the ground and conveyed by lengthy pipelines or in liquefied natural gas (LNG) tankers as it is today. Instead, it was extracted from coal in a process called “destructive distillation.” Here’s how it worked: Coal was heated within a closed container. The application of heat changed the composition of the coal. A flammable mixture of gases was released and captured, but this first yield of gas was filled with things like Sulphur and ammonia which gave it a disagreeable odor and made it less efficient to burn.

To rid the gas that would be used for illumination of these impurities, it had to be “purified” by passing it through a filtration system. This consisted of a large container of water into which was mixed a quantity of lime. As the impure gas passed through the lime-water mixture, most of the impurities became attached to the lime. The gas that emerged on the other end had been purified and could burn brightly and efficiently without disagreeable odors.

Not all of the heated coal turned to gas. Some of it melted. This was called tar and it was captured and used for the same things we use it for today. A solid substance was also left. This was called coke which was sold as a fuel for stoves and home heating systems. Because many impurities had been cooked out of it, coke was clean-burning and burned hot, so it was a very popular fuel.

But back to the gas. The purified gas would go into large storage tanks and would then flow across the city in underground pipes. These worked fine and were as safe as advertised.

The problem came from the lime-water mixture. Because the lime absorbed so many impurities from the coal gas, it had to be changed often to continue to be effective, so a huge quantity of water was used and then disposed of. For the Lowell Gas Light Company, this meant emptying the soiled lime-water containers into the gutter where it flowed into the city’s relatively new sewer system. Much of this tainted water passed through the sewers and into the Merrimack and Concord Rivers (where it did immeasurable harm to flora, fauna, and people, but that’s another story).

Not all of the contaminated lime-water passed directly into the river. Some of it took detours from the main sewer lines and into the pipes that carried sewerage from newly installed indoor toilets in the bathrooms of some residences. Among the many pollutants in this water were flammable gases that were by-products of the coal gas process. While embedded in water, these substances were inert. But when the water that was carrying them was exposed to air, the substances were released as flammable gas.

In an unfortunate number of cases, the first time this tainted water was exposed to air was when it backed up into the bowl of some unsuspecting resident’s toilet. Since smoking while using the bathroom was apparently a popular practice back then, the collision of flammable gas escaping from the toilet with a lit cigarette caused some unfortunate instances of combustion.

Soon after this cause-and-effect relationship was established in a series of negligence lawsuits, the Lowell Gas Light Company took better care in disposing of the liquid by-products of its coal gas manufacturing process and Lowell toilets ceased to explode, at least until Animal House premiered.