The primary concern at any gas emergency is the likelihood of an explosion. Accumulated explosive gas can be deadly if it reaches an ignition source, even when firefighters are far away. According to John Norman’s Fire Officer’s Handbook of Tactics (fourth ed.), gas explosions can create far greater forces, collapsing walls and even entire buildings, sending debris great distances. Hazardous gas emergencies can be deadly and destructive for civilians and firefighters alike.

Gas emergencies present a unique threat to the safety of firefighters. In the metropolitan New York area, several devastating gas explosions have occurred recently, such as in New York City’s East Village (2015); Paterson, New Jersey (2016); Trenton, New Jersey (2016); and the fatal 2016 Bronx, New York, explosion that killed Fire Department of New York Deputy Chief Michael J. Fahy. Many more gas explosions have been documented in the New York metropolitan area and throughout the United States.

Read more: Gas Emergencies: 10 Life-Safety Tactics