Sewer system likely to blame for school stink
Initial tests suggest a nearby oil and gas pad wasn’t the source of hydrogen sulfide gas detected at Grand Valley Middle School in Battlement Mesa Wednesday, and the local school superintendent said he believes the source was likely the school sewer system.
Hydrogen sulfide also is referred to as sewer gas, but can be associated with oil and gas development and can be harmful or even fatal at high enough levels. While it’s not common with oil and gas operations locally, a company had issues with the gas at wells in rural areas outside Parachute several years ago.
Students at the middle school were evacuated Wednesday morning to a nearby elementary school building after staff noticed odors. The Grand Valley Fire Department detected low levels of hydrogen sulfide at the middle school in the late morning, but students were returned to the building by the end of the school day after the gas was no longer detected.
The fire department again detected no hydrogen sulfide early Thursday, and school resumed as normal.
Rob Ferguson, the department’s deputy fire chief, said the department checked an Ursa Resources gas pad near the school Wednesday but no hydrogen sulfide was detected. He added that the wind was blowing from the school toward the pad at the time the odor was noticed.
Garfield County environmental health staff took air samples to test for volatile organic compounds and try to determine the odor’s source. County spokesperson Renelle Lott said the results won’t be received for several weeks.
Ken Haptonstall, superintendent of Garfield County School District 16 — and incidentally the finalist named Thursday by District 51 in its superintendent search — said he suspects the odor resulted from a sewer line backup that can occur when a sewer trap doesn’t have enough water in it. He said the district is looking at the issue of trying to keep adequate water in the line.
Don Simpson, an Ursa vice president, said the nearest well on the Ursa pad is 1,584 feet from the school. Most of the wells on the pad are in production, while hydraulic fracturing is being completed on the last two.
Simpson said Ursa officials responded immediately to check on its nearby facility when the odor issue arose.
Colorado currently requires a minimum 1,000-foot setback between schools and oil and gas facilities. A bill requiring the setback to apply instead to the school property line died this week in a Senate committee.
Several years ago, hydrogen sulfide was determined to exist in most of the 353 wells then being operated by Noble Energy outside Parachute. Some wells had levels high enough to potentially affect human health, but only if the gas escaped closed oil and gas systems.
Noble’s local wells are now owned by Caerus Oil and Gas.
Simpson said Ursa’s local oil and gas operations are free of hydrogen sulfide, other than perhaps some occasional trace readings, which he believes have reached about 3 parts per million at most.
Ferguson said the Occupational Safety and Health Administration considers hydrogen sulfide to be safe at continuous exposure levels below 10 ppm over eight hours. He said the readings Wednesday at the school included one spike to 6 ppm but otherwise ranged from 0 to 1 ppm.