Business Insider writes that New York City sees an average of six manhole explosions a day, and they are doozies. In 2019, Inman Mussud was escorting his son to school when a manhole explosion lifted their cab off the ground. Mussud said his head crashed against the car roof, as did his son’s. The first week of February 2015 saw 600 such explosions. In one of those instances, a 71-year-old man narrowly cheated death when an airborne manhole cover clocked him on the noggin. New York Fire Department Battalion Chief Steve Corcoran told the New York Daily News that the lid flew 50 feet into the air after a subterranean explosion and landed a “glancing blow” on the septuagenerian’s skull.

So what makes the bowels of the street go boom? According to How Stuff Works, it usually works like this: underground wires become exposed by caustic chemicals gnawing rats, or age-related decay. Business Insider adds that in the winter, corrosion results from rock-salt-saturated water seeping through the ground onto wires. Because these cables carry as much as 13,000 volts of electricity, they can ignite insulation made from paper, lead, and rubber. The flames cause built-up manhole gas to combust, sending lids that weigh 85 to 300 pounds (35 to 136 kilograms) hurtling skyward. Essentially, the street accidentally lights its own farts.