Residents of Third Avenue West in Grand Marais had an extremely unpleasant, but not disastrous experience, on Wednesday, July 22, when utility work caused sewer gas to enter several homes.
At about 5:00 p.m. on July 22, a Third Avenue homeowner heard “loud sucking, gurgling noises in the drain pipes throughout the house.” The homeowner also noticed a smell she believed to be sewer gas. With that assumption, the individual worked to refill the traps in plumbing throughout the house. Another person in the home looked outside to try to find the cause.
The homeowner discovered employees of Empire Pipe Service working at the corner of Fourth Street and Third Avenue West. The workers were flushing the sewer lines with high-pressure water jets in preparation for checking the lines with a camera, a procedure necessary to complete the sewer, water and roadwork project begun last summer.
Concerned that the work was what caused the odor in his home, and concerned that it may harm people in the houses on the street, the homeowner asked the crew to stop, but the workers said they needed to finish the job.
The homeowner contacted neighbors—of eight houses reached, five had evidence of empty traps and sewer gas leakage. One individual had left the house because of difficulty breathing, unaware of what was causing the problem.
Still concerned, a call was made to the Grand Marais Public Utility Commission (PUC) and long-time Distribution Operator Steve DuChien responded. He contacted the on-site engineer from Short, Elliot, Hendrickson (SEH) Engineering, who immediately halted the flushing phase of the inspection. The homeowner was relieved that the engineer conducted door-to-door visits to ensure that no one had been adversely affected by the escaped sewer gas. PUC Water & Wastewater Supervisor Tom Nelson accompanied the engineer to check on procedures that had been followed.
Nelson said the company had been contracted to clean and televise the sewer lines as part of the contractual agreement for the street project. He said the process gives the city an important record of where individual systems tie into the municipal system. “It’s conducted as kind of a warranty,” said Nelson.
The cleaning of the sewer lines was halted and the contractor completed televising the lines only.
Nelson explained that when lines are cleaned, there can be complications— water can be forced up the sewer pipes and cause bubbling out of the toilet—or, water can be sucked out of the trap, which is what happened in this case. He said sewer gas should be emitted through the toilet’s air vent, but he said the lines must have been “very tight.” He added that it is very rare for this to happen. “We have cleaned 20-some blocks on previous projects,” said Nelson. “And we never had this happen.”
Sewer gas often has a “rotten egg” smell due to the hydrogen sulfide content. Exposure to low levels of this chemical can irritate the eyes, cause a cough or sore throat, shortness of breath, and fluid accumulation in the lungs. Prolonged low-level exposure may cause fatigue, loss of appetite, headaches, irritability, poor memory, and dizziness. High concentrations of hydrogen sulfide can produce olfactory fatigue, whereby the scent becomes undetectable. At very high concentrations, hydrogen sulfide can cause loss of consciousness and death.
Fortunately, the remedy is very simple. “All you have to do is run water in the drain,” Nelson said.
One resident asked why homeowners were not notified that this procedure was to take place so they could have been prepared for complications. Nelson said the Public Utilities Commission has not done this in the past, but said that would be considered. “It would be a good idea to do that, just like we let people know when their water is going to be turned off for a project.”
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