Dennis Port, MA – Four people were evaluated after high levels of carbon monoxide were detected in a building this afternoon.

Firefighters responded to a carbon monoxide alarm at 677 Main St. (Route 28) at 3:36 p.m., fire Capt. Robert Marseglia said.

A gasoline-powered motor operating a pump in a basement is believed to be the cause of the “high levels” of the gas, Marseglia said.

Four people were evaluated, and one was taken to Cape Cod Hospital as a precaution, he said.

To avoid carbon monoxide poisoning, nothing gas-powered should be run indoors, not even in a garage or basement, Marseglia said.