A volatile organic compound caused the noxious odor that spurred dozens of Skippack Township residents to be evacuated from their homes Sunday night, though officials are still working to determine the exact substance involved.
Emergency crews received a call about a mysterious odor at the Fairlawn Court townhouses at about 5:45 p.m. Sunday. About 150 houses in the Montgomery County development were evacuated as authorities responded to the odor and investigated.
Fire officials said early this morning that high readings of a volatile organic compound had been found in basements there and was coming from sump pumps.
But the specific compound that caused the odor and its source remain unknown.
It would be "pure speculation" to say what happened, Skippack Fire Company Chief Haydn Marriott said at a morning news conference. He said the substance was "some sort of hydrocarbon," but acknowledged that was a broad category.
Water and air samples have been sent to laboratories for testing, and Marriott said officials hoped to learn more this afternoon.
"We just don't have a whole lot of information until we get the results back from the lab," he said.
Volatile organic compounds include a variety of chemicals that are emitted as gases, according to the Environmental Protection Agency. Some can cause irritation to the eyes, nose and throat; headaches; nausea; loss of coordination; and damage to the liver, kidney and central nervous system, the EPA says, and have been linked to cancer in humans and animals.
High VOC levels were found in multiple homes in the development, the fire company said.
The odor was initially identified as hydrogen cyanide, but Marriott said this morning authorities believed that reading was a false positive.
Utility companies have checked their equipment in the area, Marriott said, and found nothing operating abnormally.
All residents on North Gorski Lane, Karlyn Lane, Alana Lane, Elm Court, Red Oak Court and with an address of 955 or greater on Dogwood Lane should have their homes tested before returning. Testing can be scheduled by calling 610-454-0909 between 8 a.m. and 8 p.m.
The Red Cross of Southeastern Pennsylvania responded to the scene to assist some families who were displaced. The Red Paw Relief team was also helping pets that needed emergency shelter.