Delavan, WI – Officials are crediting carbon monoxide detectors with alerting authorities to a potentially dangerous situation after a portable generator filled several buildings with the deadly gas.

At 2:33 p.m. Monday, Delavan police and firefighters responded to 239 E. Walworth Ave. for a report of several carbon monoxide alarms going off, according to a news release from the Delavan Police Department.

Firefighters found high levels of carbon monoxide in the basement and first and second floors of the four-story building, according to the release. Carbon monoxide was also found in high levels in businesses in adjoining buildings.

An investigation showed that the utility company Monday morning had disconnected the power to the Mr. Taco restaurant, 239 E. Walworth Ave.

The store manager, Rosalio Mondragon-Vanegas, bought a portable generator to operate the freezers in his restaurant while the power was out, according to the release.

The generator was in the basement for more than two hours and was not properly ventilated, according to the release.

Eight apartments and three other businesses were affected. Businesses in the same building include Dulceria Acapulco, 235 E. Walworth Ave.; Scene II, 237 E. Walworth Ave., and Guanajuato, 233 E. Walworth Ave.

Only two people were home at the time, but it could have been much worse, said Delavan Fire Chief Tim O’Neill.

The businesses and apartments were evacuated for more than two hours while firefighters work to ventilate the building.

Carbon monoxide is a toxic gas and is odorless and tasteless.

Delavan Fire Chief Tim O’Neill credited building inspector Fred Walling for enforcing the carbon monoxide detector requirements in such buildings.

O’Neill cited a similar carbon monoxide incident in Maryland on Monday that had a different outcome. A father and seven children were discovered dead in their Maryland home of carbon monoxide poisoning. The father had bought a gas generator to heat the house. The generator was found, out of gas, in the kitchen.

Mondragon-Vanegas was cited for a fire code violation.