Officials in Keene, New Hampshire warned residents Wednesday that a "system error" at a distribution plant could lead to high carbon monoxide levels inside buildings.
The Keene Public Works department said in a Twitter message to Liberty Utilities customers the error "caused the possibility" for appliances and heaters to produce high carbon monoxide levels.
If high levels of carbon monoxide are detected, residents should evacuate and call 911, the department said.
The Keene fire department said it was working with the utility to check on customers to ensure their homes did not have high levels.
Fire officials said at as of Wednesday morning, they had not detected high levels at customer's homes and added they would continue to check with customers until the issue was resolved.