Amarillo, TX- By Cheryl Berzanskis, Amarillo Globe

Advo Companies will be closed today because of a carbon monoxide scare that led to the evacuation of about 100 people Monday.

Carbon monoxide alarms in the building’s basement sounded at about 11:17 a.m. People were out of the building in less than three minutes, said Executive Director Carla Hughes.

Four people were taken to the hospital by ambulance, but all were released later that afternoon, Hughes said.

Clients have limited ability to communicate, so sending them to the hospital was a precaution, she said.

The company operates a workshop for disabled adults at 2736 W. 10th Ave. Everyone was sent home Monday afternoon.

There are four CO alarms in the 60,000-square-foot building, she said.

“We have standard procedures that we follow and do monthly fire drills,” Hughes said.

Amarillo firefighters carried CO monitors in the building to measure gas concentrations. The monitors can measure down to 1 part per million, said Capt. Bob Johnson of the Amarillo Fire Department.

Shortly after the evacuation, firefighters’ meters registered between 47 ppm and 80 ppm, he said.

Carbon monoxide is a colorless, odorless, poisonous gas produced by incomplete burning of carbon-based fuels, according to the Web site of the Environmental Protection Agency.

The danger of carbon monoxide is in its elevated level over time, Johnson said, with minor symptoms reversible in fresh air.

Of the people evacuated, 70 were clients and 25 were staff.

Hughes said the source of the carbon monoxide was traced to a faulty water heater, which crews will repair today, clearing the way for the building to reopen for business Wednesday.