London fire officials are warning residents to always properly extinguish their smoking materials after a discarded joint caused a fire at a Western residence room.

Early Friday morning, emergency crews were called to a dorm room at O'Neil Residence.

The blaze was started after a student placed a doobie in a recycling bin near a bed, which caught fire.

No one was hurt. Damage is pegged at $2000.

Officials also say the smoke alarm was covered with a bag to make it inoperable.

“Any careless discard of smoking materials can cause significant fires with potential for serious injury or loss of life. Early detection is key when any fire occurs,” said acting deputy chief Jack Burt in a news release.

“Altering or impairing a smoke alarm places yourself and others at great risk. I encourage those who smoke to do so responsibly. Smoke outside, use a deep ashtray and when you put it out, be sure to put it right out.”