PALMER, Mass. (WWLP) – The cause of the fire on High Street in Palmer on Wednesday has been determined.

State Department of Fire Services Spokesperson Jake Wark told 22News that at around 3:30 a.m. firefighters were called to the area of 4454 High St. for smoke coming from the front left corner of the second floor. An adult woman was taken to the hospital after being injured in attempting to put out the fire.

The fire was determined to be caused by an air conditioner that was plugged into an extension cord, which in turn was plugged into a power strip and another extension cord. The electrical fire then ignited combustible materials in the area. Fire officials remind residents that heavy appliances should be plugged directly into wall outlets.

This is the second fire in less than a week caused by an air conditioner. On Saturday afternoon, firefighters were called to Bigelow Road in Webster, where a resident’s air conditioner cord caused a fire after it was pinched between the bedframe and the wall.

“An occupant reported that the circuit breaker panel had tripped several times in the hours before the fire,” said Webster Fire Chief Brian C. Hickey. “Blowing fuses or tripping the circuit breaker frequently is a warning sign that you should call a professional electrician. If you see arcs or sparks, hear a sizzling or burning sound, or smell something burning, call your fire department right away.”

“This summer’s heat has been brutal, and many folks are turning up the air conditioners,” said Chief Bernat. “If you do, remember that these appliances should always be plugged directly into a wall outlet. Using an extension cord or power strip could cause a fire like the one we saw here.”

“Extension cords and power strips are for temporary use and can’t safely handle the high current that air conditioners, space heaters, and other heavy appliances use,” said State Fire Marshal Ostroskey. “Plug these devices into a wall outlet to prevent a fire, and keep the cord clear of doorways and furniture that might damage or pinch them.”

“Fortunately, the resident was awoken by the noise and flash of light,” Chief Bernat said. “There were no working smoke alarms in the residence, and this could very easily have been a terrible tragedy.”