FLINT, MI -- A hand-written log book shows workers preparing to put the Flint water treatment plant into operation in 2013 didn't use a standard pump but a hole in the floor of the building to feed chemicals into Flint River water.

Special prosecutor Todd Flood pushed the point as preliminary examinations continued Monday, May 14, in the criminal cases against four current and former employees of the Michigan Department of Environmental Quality in Genesee District Court.

Prosecutors have contended DEQ regulators should have known there were serious problems with Flint's water system even before, but certainly after, the city's water source was changed in April 2014 and employees attempted to treat river water for the first time in decades.

The plant continued to run for 17 months despite rising levels of bacteria and chlorine byproduct in city water and suspicions that the new water could have triggered outbreaks of Legionnaires' disease.

The log book, dated Sept. 16, 2013, noted the plant took delivery of polymers and notes, "We are putting it on the second floor in the mechanical room and feeding through a hole in the floor."

Flood told Judge Jennifer Manley that he will also show other chemicals were dumped into Flint's water supply through the same hole in the floor of the plant because the city didn't have equipment that's typically used.

"Is that the normal protocol for operating a plant?" Flood asked. "They didn't have a pump. They were just dumping it in a hole."

Dave Jansen, a recently retired executive in the office of Genesee County Drain Commissioner Jeff Wright, testified that the practice "is not typical" of water treatment plants but attorneys for the DEQ employees said the same plant log showed polymers appear to have been measured with the dosage also noted in the log.

Jansen's testimony came on the ninth day of the preliminary exams for Liane Shekter-Smith, 57; Stephen Busch, 42; Patrick Cook, 54; and Michael Prysby, 54.

Flood has said he plans to pursue involuntary manslaughter charges against Busch and Shekter-Smith.

Busch, a district supervisor, also faces six additional criminal charges.

Shekter-Smith, former chief of the DEQ's Office of Drinking Water and Municipal Assistance, is also charged with misconduct in office and willful neglect of duty.

Shekter-Smith is the only state government employee who lost her job as a result of the water emergency.

Prysby, a district engineer who was responsible for Flint, is charged with two counts each of misconduct in office, tampering with evidence and violation of the Safe Drinking Water Act.

Cook, a specialist for the DEQ's Community Drinking Water Unit, is charged with willful neglect of duty, misconduct in office and conspiracy.

William Kriger, an attorney for Busch, argued that his client acted appropriately in his oversight of Flint's water system, following past precedent with regard to requirements placed by the state on the city.

"They were following past practices," Kriger said of the role of the DEQ regulators, who never required to the city to treat the river water it used to make it less corrosive to pipes and plumbing leading to and inside homes.

Kriger was among defense attorneys who questioned Jansen Monday, reviewing monthly operating reports from the city after the plant began operating for the first time in decades.

Under questioning, Jansen said nothing in the operating reports signaled the severe problems brewing in the water system.

Jansen testified previously that after walking through the Flint water plant a few weeks before it went into operation, he was troubled by some of what he saw, including broken or inoperable equipment, inexperienced employees and no visible means to add phosphates to the water supply.

Kriger was among defense attorneys who objected to Flood's use of the log from the Flint water plant, noting it was written months before the plant started producing the city's water.

Flood said the information was relevant to charges against the DEQ employees because they could have stopped the plant operating but signed a permit allowing it to produce drinking water.