Tampa, FL – A car left running in a garage overnight led to high levels of carbon monoxide in a Carrollwood home Monday, sending five people to the hospital, Hillsborough County Fire Rescue officials said.

Three of the five were in critical condition, according to Rob Herrin, a spokesperson for Hillsborough County Fire Rescue.

First responders went to a home at 12511 Sugar Pine Way in Carrollwood at 10:22 a.m. Monday after receiving a call about a person who was unresponsive in the home, Herrin said. The call came from two men who went to the residence to check on the people there.

When officials arrived, they detected high levels of carbon monoxide from a car running overnight in a garage, Herrin said.

Hillsborough County Fire Rescue transported the three people — two men and one woman — to area hospitals in critical condition. They also took the men who checked on the home to area hospitals, where they were in stable condition.

Fire officials believe the incident was an accident, and there is currently no investigation involving law enforcement, Herrin said.

Carbon monoxide is a colorless, odorless gas, according to the Centers for Disease Control and Prevention. Furnaces, stoves, lanterns, gas ranges or burning charcoal and wood produce the gas, the agency said. Carbon Monoxide can build up in enclosed spaces — like when a running car is parked in a closed garage.

The most common symptoms of carbon monoxide poisoning are headache, dizziness, nausea, vomiting, chest pain and confusion, the agency said.

“Carbon monoxide competes with oxygen, and it always wins,” Herrin said.

The incident is a reminder for people to keep a carbon monoxide detector in their homes, Herrin said. People can pick up a carbon monoxide detector at a local hardware store, Herrin said.