Omaha, NE – A man and a woman have died of carbon monoxide poisoning after a vehicle was left running in an attached garage in a house near 56th and Spring Streets, Omaha police and fire officials said Monday.

Police said officers responded to 5614 Spring St. at 10:52 a.m. Monday to investigate the deaths.

Carbon monoxide levels in the house were measured at 400 parts per million, said Omaha Fire Battalion Chief Scott Fitzpatrick. “If it rises more than 50 parts per million, that’s when carbon monoxide gets deadly,” he said.

The names of the man and woman will be released when next of kin have been notified, police said Monday afternoon.

The Omaha Fire Department will install combination smoke and CO detectors for free for Omaha homeowners, Fitzpatrick said. People can request a detector at or by calling the department’s public education office at 402-444-3560.

According to the federal Centers for Disease Control and Prevention, 2,244 deaths in the U.S. resulted from unintentional carbon monoxide poisoning in 2010-2015, with the highest numbers of deaths each year occurring in the winter months.