SASKATOON -- An accidental fire Sunday morning at the Jim Pattison Children’s Hospital left a man with severe burns to his upper body, and was a result of a small explosion, the Saskatoon Fire Department says.

At around 2 a.m. on Sept. 13, the fire department said it was called to the emergency department of the children’s hospital.

Upon arrival, the fire department said hospital staff and nearby patients had already evacuated and security staff at the hospital had already partially extinguished the blaze with a fire-extinguisher.

In a news release, the fire department said a fire investigator determined the fire was accidental as a result of smoking and a man suffered severe burns to parts of his upper body after attempting to smoke while receiving oxygen.

The fire department said a small explosion occurred igniting a fire and causing about $1,000 in damage to the hospital.