Keene, NH – Fire officials in Keene, N.H., were investigating Wednesday after a “system error” at a utility’s distribution plant raised concerns about elevated carbon monoxide levels in this city in the southwestern part of the state.

The Keene Fire Department began tweeting about the troubling incident around 7:36 a.m.

“Emergency Notification City Gas- Liberty Utilities customers there was a system error this am at the distribution plant, it caused the possibility for appliances and heaters to produce high Carbon Monoxide levels,” the department tweeted. “If your CO alarms call 911 and evacuate @NotifyKeene”

In a follow-up tweet, the Fire Department said it was “working with Liberty Utilities to check customers to make sure there is no CO levels. The high BTU has been contained at plant however still possible to have issues at appliances and heaters. Again if CO alarms call 911 .@NotifyKeene”