Anaerobic digester death ruled accidental drowning

Robert Baenziger Jr., a Quad Cities scuba diver who failed to surface after a dive into a million-gallon anaerobic digester June 8, died of accidental drowning, according to the Office of the State Medical Examiner.

The cause and manner of Baenziger’s death was released Wednesday after an autopsy conducted last month at the office in Ankeny. The delay in releasing the information was due to a wait for toxicology reports, staff said.

Baenziger, 54, of East Moline, died around 10 a.m. June 8 when he was unable to return to the top of the liquid in the tank at Sievers Family Farm in Stockton. The farm owner had hired Baenziger, a self-employed contractor, to dive into the tank to repair an agitator cable, officials said.

“As his fiancee was trying to pull him up, there were complications and he didn’t surface,” Scott County Sheriff’s Capt. Joe Caffery said last month. “For whatever reason, he relayed to her through radio communications that he was taking his helmet off. So when she pulled the rope up, the helmet came up.”

A team of commercial divers from Chicago later recovered Baenziger’s body from inside the tank. They said he did not have on proper protective clothing or safety gear for a dive into contaminated water.

Because Baenziger was a self-employed contractor, he was exempt from Occupational Safety and Health Administration inspections, Iowa OSHA Administrator Russell Perry said. And the farm, which has 10 or fewer employees, also doesn’t fall within the purview of the worker safety agency.

The incident originally was described as happening in a manure tank, but it was in one of the farm’s two digester tanks, where cow manure and food waste are used to create methane, which can generate electricity and heat.

The Sievers Family Farm digester system, operated since 2013, is one of four on-farm digester systems in Iowa.

Baenziger’s primary job was as an independent contractor who did home repairs, but he was an experienced scuba diver, trained in the U.S. Army, who had done commercial dives at offshore oil wells and on the Mississippi River, family said last month.

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