A hazardous substance, possibly leaked from a factory or other industry, flowed through the West Elizabeth sewer system this morning.

The spill has been contained, said Ryan Kortina, operator at the sewage treatment plant.

None of the product spilled into the Monongahela River, Mr. Kortina said this afternoon.

The substance was noticed around 10:30 a.m. Treatment plant operators believe the fluid had been discharged as early as 45 minutes before it was noticed.

The substance has not been identified, and the Allegheny County Health Department was notified.

The agency also called in Hazmat teams and notified state and federal environmental authorities about the incident.

The West Elizabeth plant provides sewage treatment for the borough and for Jefferson Hills, Mr. Kortina said.

About 65 percent of the customers in the system are industrial companies, he said.

The undetermined amount of material has been contained in the sewer lines, where crews are working to clean it out, and in containment vessels near the river bank.

No injuries have been reported, although some workers have been exposed to the unknown substance.