Exhaust fumes from a gas-powered generator caused 15 people to be hospitalized with symptoms of carbon monoxide poisoning Sunday in Marshalltown. One victim died.

The generator, which ran for an undetermined amount of time in an unventilated basement of the Church of God building at 305 E. South St., let out "lethal levels" of the colorless, odorless gas, Deputy Marshalltown Fire Chief Christopher Cross said.

The building had not operated as a church for at least two years and nobody was permitted to be there, Cross said.

The generator was being used to provide light and heat in the building, which had no electric or gas service. Responders found cans full of gasoline there, according to a news release.

No further information was available about the victim who died, Cross said.

Victims were dizzy, fainting, experiencing headaches and showing "cherry red skin," he said. The call came in as a medical call and then progressed into a carbon monoxide response, he said.

Fire personnel measured 1,400 parts per million — what Cross described as an "astronomical amount" — of the gas in the air near the generator.

OSHA's permissible carbon monoxide exposure limit is 50 parts per million.

Fire, law enforcement and EMS personnel responded to the scene around 3 p.m.

Five victims were airlifted and three were taken by ambulance to hospitals in Iowa City and Des Moines. No update on the other victims' medical conditions was available Monday.

Marshalltown Mayor James Lowrance said that medical, police and fire personnel responded well to the traumatic situation.

“This was quite an event for us,” Lowrance said. “The community is just really saddened by the fact that we had a loss of life and a number of people who were hospitalized.”

The Marshalltown Fire Department is continuing to investigate the incident.

Cross reminded people to change the batteries in their smoke detectors and to avoid using internal combustion engines inside.

"Please use the products as they are intended to be used," he said, "because carbon monoxide is a silent killer."

The building has been owned since 1951 by an organization called Church of God, according to the Marshall County Auditor. The auditor's office did not have further information about that owner.