The slew of calls concerned about gas leaks on Wednesday, Oct. 10, in a Cranberry Township neighborhood were likely the result of elevated levels of mercaptan, a sulfur-containing compound intended to alert customers to even smallest of leaks, according to a statement by Columbia Gas posted to the township’s website.

Area fire departments responded to about 40 reports of natural gas smell in the Fox Run neighborhood of Cranberry Township beginning at about 3 p.m. Wednesday and continuing well into the evening. The situation prompted Columbia Gas to shut off gas to the affected homes while the problem was investigated.

Thursday, a spokesman for the gas company indicated there were no noticeable issues pointing to the increase in calls, but in a later company statement, the likely cause was defined as an elevated level of mercaptan.

“The leaks our service technicians detected on customers’ facilities and appliances were preexisting in nature and very small in most cases and not caused by elevated mercaptan levels,” the statement said. “These small leaks would likely not have been noticed when mercaptan levels were in the normal range, and it would not be uncommon to find similar kinds of leaks in neighborhoods of similar vintage.”

The statement said that “nothing on our system” indicated any impact on customer-owned natural gas lines or customer-owned natural gas appliances.

Mercaptan is a compound added to natural gas, which is odorless and colorless, because it alerts customers to the presence of natural gas. Its smell is often described as similar to that of rotten eggs.

“In this situation, it helped customers identify leaks that otherwise may not have been detected and allowed customers to take remediation actions,” Columbia Gas said in the statement.

The gas company said the mercaptan levels in that area have returned to normal levels Thursday, but the investigation will continue.

In the meantime, Columbia Gas reminded residents that now is an optimal time to prepare their household appliances for winter.

“As the region starts to experience colder weather, it is a good time to remind customers to have a qualified professionals inspect their natural gas appliances for proper venting and an adequate supply of fresh air, especially appliances located in enclosed spaces like closets or utility rooms,” Columbia Gas Communications Manager Lee Gierczynski said in a statement. “Make sure the exhaust and vent are in good repair and are not clogged or blocked.”

Customers who suspect they smell natural gas can reach Columbia Gas at 1-888-460-4332, and a service technician will be dispatched to check to conduct a thorough safety check and inspection.