INSTITUTE -- Bayer CropSciences ignored faulty equipment and overworked its employees leading up to the August 2008 explosion at the Institute plant that left two long-time workers fatally injured, according to initial findings by the U.S. Chemical Safety and Hazard Investigation Board.

The CSB released its initial findings at a news conference Thursday. A final report is expected by year’s end. John Bresland, chairman of the U.S. Chemical Safety Board, said Bayer has been uncooperative in the CSB’s investigation and has hindered its efforts.

Bayer exchanged correspondence with the U.S. Coast Guard in attempts to keep more than 1,000 pages involving MIC from investigators, according to a recent congressional investigation.

“This issue of sensitive security information has basically brought our investigation to a halt for the last 10 weeks,” Bresland said. “I’m deeply disappointed with Bayer’s conduct in this matter.”

He said it is fortunate the MIC tank that sat just 80 feet from the explosion was not breached. The tank contains more than 13,000 pounds of MIC, and piping containing MIC was located in overhead pipe racks in the area, he said.

The CSB will review engineering studies of the MIC tank’s location and determine whether relocating the vessel is warranted.

John Vorderbrueggen, the CSB’s investigation supervisor in the Bayer explosion, said an extended maintenance shutdown preceded the explosion.

Workers at the plant were fatigued after averaging 20 hours a week in overtime during an overhaul the three months leading up to the explosion, Vorderbrueggen said.

They repeatedly worked 12 to 18 hour days with few days off, he said.

In addition, operators were not comfortable with a new mouse-based control system that replaced another computer system in the overhaul, he said.

“The control screens were completely different. From the personnel interviews, our team concluded the operator training program was inadequate,” Vorderbrueggen said.

Written operating procedures were out of date and did not include all operating and startup steps, he said.

And Bayer had serious lapses in its safety management and overrode safety features that could have avoided the explosion, investigators said.

A heater on the Methomyl residue tank was too small to process chemicals — employees had to override safety features to begin the decomposition of Methomyl, investigators found.

This involved deactivating safety interlocks controlling the flow of chemicals into the residue treater, Vorderbrueggen said.

“Operators told the CSB that (the heater) was incapable of heating the contents of the residue treater to the temperature required to begin the controlled decomposition of the Methomyl,” he said.

The rapidly decomposing Methomyl made temperatures rise sharply inside the tank, so the operator asked that someone check for a blockage on the vent line, he said.

The vessel relief valves opened to release pressure, but they were overcome and could not react quickly enough, Vorderbrueggen said.

Tired workers forgot to prefill the residue treater with solvent, a critical step in the startup process meant to keep the Methomyl concentration below 1 percent, Vorderbrueggen said. A concentration above this would cause the treater to violently rupture, according to safety analyses and operator procedures.

“As a result of equipment deficiencies, improper procedures and lack of training on the new computer control equipment, the vessel was charged with as much as 20 percent concentration of Methomyl on the night of the explosion,” Vorderbrueggen said. “It was a runaway chemical reaction.”

The residue treater suddenly ruptured, ejecting as much as 2,500 gallons of highly flammable and very toxic chemicals, he said. The chemicals poured over Barry Withrow and Bill Oxley, the two workers who died from injuries from the explosion.

“The 5,500 pound vessel careened into the unit, destroying steel columns, pipes and other equipment,” Vorderbrueggen said.

Bayer knew about the undersized vessel heater for years that led employees to work around safety features.

“Workarounds became the norm,” he said.

Bresland said he would not want to live near the Bayer plant in Institute with its present safety plan. He has operated numerous large chemical facilities along the east coast during his career.

The CSB’s findings and recommendations are meant to keep similar situations from reoccurring.

“We’re looking at the technologies used by some companies, notably DuPont in LaPort, Texas. These companies produce and use MIC as needed immediately for production, eliminating the need for storage,” Bresland said.

The Institute Bayer CropSciences plant includes more than 400 acres and has more than 500 employees.