A local couple and their 7-year-old son were rushed to the hospital Monday afternoon after suffering carbon monoxide poisoning in their West Side apartment.

David Leon, his wife, Elsa, and their son, David Jr., were all being treated at Bridgeport Hospital. They were expected to be released later in the day.

“If this had happened in the middle of the night it could have much worse circumstances,” said Assistant Fire Chief Christopher Martin.

Martin said about 1 p.m. they received a call from Elsa Leon complaining the family was feeling very ill in its second-floor Maplewood Avenue apartment.

“When we got there the husband, David Leon, was in the lobby. He managed to open the door for us before collapsing,” Martin related.

Realizing it was probably a case of carbon monoxide poisoning, Martin said, he immediately gave the order to “mask up.”

When they got through the apartment door, he said, firefighters immediately detected high levels of the clear, odorless gas. They found the woman and her son lying on the apartment floor and carried them out.

Martin said the building, the former Maplewood School, is made up of individual apartment units each with its own gas furnace. He said the furnace in the Leon’s apartment was found to have a defect causing the carbon monoxide emission.

The building is owned by the Mutual Housing Association of Southwestern Connecticut, a nonprofit housing development corporation.

Fire Lt. David Purcell said the carbon monoxide level in the Leon’s apartment was 225 parts per million. According to the U.S. Consumer Product Safety Commission, sustained levels of 200 parts per million of carbon monoxide can lead to death.

About 170 people in the U.S. die from carbon monoxide poisoning every year.