"It was a domino effect," Edinburg Fire Chief Shawn Snider told the Houston Chronicle. "One (worker) went down (in the manhole), and the next went down to get the first, and then the third guy went down to get the second and he was incapacitated by the gases as well."
Francisco Hernandez, 24, and Javier Cruz, 22, employees of L&B Vector Service, were not wearing fall protection equipment or respirators and had not monitored the air in the manhole. If they had, they would have found high levels of methane and hydrogen sulfide gases, said Snider.
Snider called in police and OSHA investigators after his department recovered the bodies and rescued Robert L. Dose, a supervisor at Jimerson Underground. Jimerson had a contract to repair sewer lines for the city of Edinburg and L&B Vector Service was a subcontractor for Jimerson.
The rescue team found Dose unconscious in chest-high water at the bottom of the manhole. They found another worker about 10 feet down the sewer line and the third worker underwater at the bottom of the manhole under Dose.
"It's really a sad situation," Snider told the Houston Chronicle. Noting the incident could have been prevented, Snider added, "There is no excuse for not providing safety equipment for protecting your workers."