Back in April, Ellicott City Avishek Sengupta jumped off a 15-foot plank into a freezing pool of muddy water in West Virginia. And he did it on purpose: it was one of the obstacles featured in the Tough Mudder extreme endurance event that Sengupta and a group of co-workers had enrolled in. These races are often billed as being fun romps through the mud, and often they’re just that. But in the wake of Sengupta’s death, some people are wondering whether the races are too unsafe to keep going as they have been.

The New York Times has a great write-up of what actually took place on that chilly April morning, and how Sengupta went from splashing through the mud  to drowning in a muddy pond. According to his teammates, even after they realized that Sengupta was still underwater, it took them several minutes to get the attention of the race’s lifeguards, and between seven and ten minutes before Sengupta was pulled out of the water. He never regained consciousness. (He’s also not the only one to have suffered severe injuries or death during one of these races; in 2011, a college student was paralyzed during a Warrior Dash obstacle course. According to Outside Magazine, two participants died of heat stroke during other Warrior Dash races, and a man drowned in a river during the Original Mud Run in Fort Worth in 2012.)

Tough Mudder is hosting another race on the same course on October 19 and 20. Bijon Sengupta, Avishek’s father, told the Times that he was “extremely disappointed” that the Walk the Plank obstacle — the one that killed his son — is still part of the race. “I’m concerned about other kids, too,” he said. “I don’t want this to happen to anybody else. It’s an accident waiting to happen.”