Three adult brothers in western Ohio died after being trapped in a farm’s manure pit, ABC News reports. Gary (who was 37), Todd (31), and Brad (35) Wuebker were found unconscious while fixing a manure pump Tuesday afternoon at their family farm in the village of St. Henry. Their mother called 911; a second call to dispatchers alerted first responders the men had been trapped, Fox 8 News reports. “I need some help here,” said the 911 caller. “I’ve got all three boys down in the pit.” A local dive team pulled the men from the pit; they were later pronounced dead at Wayne Lutheran Hospital.

While it is not yet known how the Wuebkers got trapped in the pit, a preliminary autopsy revealed that then men died from asphyxiation. Manure pits can be extremely dangerous as methane can be fatal for anyone exposed for lengthy periods of time. “Nationwide data shows that most deaths occur during the summer months, a time when many producers are emptying pits,” according to the National Agricultural Safety Database website.