Are there health risks tied to sewer drain smoke tests?

The Sandpoint sanitary sewer system is getting tested for leaks this week. Smoke testing is used to locate problem areas that need repair. This generally includes leaks from breaks, broken manholes, and uncapped lines.

In a notice posted on doors showing the testing schedule, which were based upon the manufacturer’s claims, it’s stated that the smoke is non-toxic. A further examination, though, of the process and chemicals used revealed some important health risks.

Smoke testing allows city crews to detect where storm water may be entering the sewage pipes. This is called inflow. When run off during a heavy rain or snow melt enters the sewer lines this puts extra demands on the treatment facilities.

The testing process involves forcing a visible and artificially produced smoke, along with high volumes of air, into the sewer pipes and surveying where it comes out. It is blown in under moderate pressure using a small engine that sits on top of a sewer access hole. If it comes out a storm drain or the ground, you’ve got a leak.

Smoke may also be forced into your home’s sewer pipes and could enter your residence due to infrequently used drain pipes and/or a defect in your sewer pipes. If all goes well, it will just go up the vents and exit on top of your roof. If things don’t go so well, smoke may enter your living areas. This does not mean you have a fire, this is not that kind of smoke. It could mean chemical gasses from the main sewer lines are entering through your pipes.

This might simply be an indication you do not have water in a trap below a fixture or floor drain because it has all dried out. Or it could be a sign one of your sewer pipe fittings are loose, a toilet seal is leaking, you have an un-trapped washing machine, or a garbage disposal is not installed correctly.

It’s important to check these out. You do not want to be breathing sewer gases. These can have toxic chemicals including hydrogen sulfide, ammonia, methane, esters, carbon monoxide, sulfur dioxide and nitrogen oxides. If you see and smell smoke during the testing this means sewer gases may be present as well.

Smoke testing is one of the most cost-effective ways to check for sewer leaks. It’s important these leaks are found and repaired. By testing, the city is making a fine effort to keep everything flowing, safe, and operating efficiently.

The smoke used can be created in different ways. One, through a chemical reaction of zinc chloride in a device called a smoke candle. This is similar to a 4th of July smoke bomb. In another, a petroleum oil is heated by the hot exhaust stream of a small engine and forced into the sewer. The city of Sandpoint is using the petroleum method this week.

Either way, we should all know by now smoke is not healthy to breathe. Notify city crews in your area if you see or smell smoke, especially if you have respiratory issues. Breathing chemicals like this can cause irritation, even inflammation, of the respiratory tract and mucous membranes. Vaporized petroleum distillates or hydrated zinc chloride is not healthy for the lungs or our brains.

You may be able to see and smell the smoke while the test is occurring, especially if it is coming into your house or out a sewer drain next to your driveway. If you do, I would suggest you don’t breathe it due to the potential health risks.

Make sure you run water into all your drains to fill up the traps fully and flush the toilets. This will restrict smoke and gases from entering your home there. If you have pets, put them in an area without plumbing and leave the windows open. Ventilate your house well by opening the windows and doors when you get home.

Scott Porter, a functional medicine pharmacist, is the director of the Center for Functional Nutrition at Sandpoint Super Drug. He can be reached at scott@sandpointsuperdrug.com.