Mystery gas forces people from homes

• A volatile organic compound was coming from sump pumps, a fire department says


• About 150 homes have been evacuated in Skippack Township

(CNN) -- A strong odor from an unidentified gas led firefighters to evacuate 150 homes in a Philadelphia-area community, a fire department said.

Firefighters began evacuating homes from part of Skippack Township after a resident complained of an odor early Sunday evening, the township's fire department said.

With the help of meters, firefighters learned a gaseous volatile organic compound was coming from the basement sump pumps in several homes, the department said.

They didn't immediately know what the gas was.

Volatile organic compounds cover a wide range of gases that can come from thousands of products, such as paints and lacquers, paint strippers, cleaning supplies, pesticides and permanent markers, according to the Environmental Protection Agency.

Many residents waited outside their homes as firefighters checked the buildings Sunday night, according to CNN affiliate WPVI, but the evacuations still were in effect Monday morning.

The Red Cross opened a shelter at an elementary school for evacuated residents who needed a place to stay, the fire department said.

Skippack Township is about 25 miles northwest of Philadelphia.

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