QUEENSBURY - A potentially deadly level of carbon monoxide filled a Queensbury restaurant Saturday, sending 42 people to an area hospital.

Most of the employees and customers of the Log Jam restaurant were treated and released. Two were flown to another hospital for more specialized treatment, said Queensbury Central Fire Department Chief Joseph DuPrey. No further details on their location or condition were immediately available.

The dining room was filled with 5,000 parts per million of carbon monoxide gas after the restaurant's water heater in the basement stopped venting exhaust properly, DuPrey said.

At that level people can get sick within minutes and died within an hour, DuPrey said.

“It's not uncommon for us to go to a residential home and see maybe 10 or 15 or 20 (parts per million,” DuPrey said. “To have 5000 parts per million is an extremely hazardous condition.”

Authorities were notified at 9:45 p.m. after a customer fainted.

The restaurant was evacuated within minutes of the emergency crew's arrival.

Restaurant managers were unavailable for comment and the restaurant was closed Sunday.

National Grid turned off the lead and the town of Queensbury's code enforcement office will work with the restaurant to ensure that the water heater meets code.