Most fatal accident investigations find precursors or missed opportunities that could have prevented the tragedy. But the death of a Chicago suburb public works employee who became trapped in an underground vault that filled with water may qualify as one that could never have been foreseen.

 A watermain break while the worker, Matt Heiden, was in the vault, flooded the chamber and drowned him.

In a press release, the Village of Westmont said Heiden was unresponsive when he was removed from the underground water main vault about an hour after the accident was reported at 11:45 a.m. on Feb. 23. 

Larry McIntyre, a spokesperson for the Village of Westmont, said Heiden was performing scheduled maintenance on the water system beneath a manhole 

“He was doing repairs when a freak accident occurred and water rushed in,” McIntyre said. 

McIntyre said state labor officials will take the lead in investigating what occurred. Heiden had worked as a seasonal employee in the village’s public works department between 2019 and 2021. He was hired as a part-time water maintenance worker in September 2021 and had recently become full-time, according to the village.

Few confined space accidents have involved drownings.

The Bureau of Labor Statistics reported in 2020 that there were 41 deaths in sewers, manholes, or storm drains between 2011 and 2018. All were related to inhalation of a harmful substance. 

In those years, there were also 203 deaths in ditches, channels, trenches and excavations that were due to collapses. 

A spokesperson for the U.S. Dept. of Labor called the incident that killed Heiden “something of an anomaly.” 

Erik Kambarian, chief, Division of Occupational Safety and Health for Illinois OSHA, said the agency inspected the site the day after the accident and would report the results of its investigation within six months.