Faria was charged with involuntary manslaughter in the deaths of Enrique Araiza and Jose Alatorre, who drowned after climbing into a 30-foot-deep pipe in a manure pit.
Prosecutor Gale Filter claimed the men did not receive proper training on the hazards of confined spaces and were not wearing appropriate personal protective equipment, such as respirators.
"There is no way you are going to go into a dairy pit if you have knowledge of what those dangers are," Filter said.
The defense countered that although the state knew about the hazards associated with manure pits as far back as 1990, Cal-OSHA did not cite Aguiar-Faria & Sons Dairy for confined space violations until the men drowned in 2001.
Defense attorney Kirk McAllister pointed out that when the Gustine Fire Department responded to the call about the men, they did not have the necessary equipment or training to retrieve the men and had to request help from the Merced Fire Department. He added that the firefighter who climbed into the shaft to retrieve the bodies had never made a confined-space rescue.
One witness testified that he climbed into the same shaft 2 years before the fatal incident to make a repair and was not wearing a respirator.
"That is the man who was trained by a company doing service for dairies," McAllister told the Modesto Bee, noting that if he wasn't wearing proper protective equipment, that Faria should not be expected to know that his employees should receive special training and wear PPE to do so.
Filter disagreed, saying the deaths were the result of "indifference, apathy and greed" on the part of Faria.
The jury is expected to reach a decision this week.