A gas leak set forth an explosion and blaze that injured several people, including two firefighters, 20 years ago today.

The Woburn Nursing Home was undergoing plumbing work when the gas began to leak due to an error and exploded at 3:45 p.m., reported the National Fire Protection Agency. According to the NFPA, the explosion blew part of the building's roof into a nearby cemetery and started a fire.

The three-story building housed 101 elderly residents, who were quickly evacuated by firefighters, staff, neighbors and construction workers, said the NFPA. The building's 21 sprinklers were operational and helped keep the fire confined to the explosion area.

The fire rose to four-alarms and was extinguished by 5:15 p.m. Although it caused approximately $1.5 million in damages, no one died in the fire, said the NFPA.