Abstract: At approximately 8:00 a.m. on August 15, 2013, Employees #1 and #4 were setting up two vessels, diaphragm pumps, and hoses to perform a test water heating procedure in the pilot plant area at Pulcra Chemicals, LLC. No chemicals were used during the testing. This was not the employee's usual job task. The vessels that were being used were a 100 gallon atmospheric mixing vessel and a 350 gallon International bulk container (IBC) tote. The set-up was conducted to test the heating of water in the 100 gallon mixing vessel to approximately 80 degree Celsius and 176 degrees Fahrenheit by using steam heated water from the IBC tote and circulating it through the jacket on the 100 gallon vessel using pumps. On the lid there was a 3 in. metal filling cap that housed a 5:1 vent pressure relief valve that was set to activate at 5 lbs per square inch of pressure. There was not a pressure gauge on the IBC tote and it contained decals that stated Caution do not pressurize this tank. This unit had a temperature gauge on it. At approximately 9:00 a.m., Employee #1 filled the IBC tote with approximately 250 to 275 gallons of water. The tote did not contain a fill gauge and the employee filled the unit so that it would not have to be refilled for the duration of the heating process. The employee began the heating procedure. The water in the 100 gallon vessel began to heat up when the temperature gauge read 30 to 40 degrees Celsius and 86 to 104 degrees Fahrenheit. At this time, Employee #1 alerted Employees #2 and #3 that the process was underway. A coworker came over to Employees #1, #2, and #3 when the temperature read approximately 65 degrees Celsius 149 degrees and Fahrenheit and started discussing the chemical process that would be put in place. The employees walked over to the laboratory area of the Pulcra Chemicals plant that was approximately 600 ft from the pilot plant area. The temperature of the 100 gallon mixing tank was at 74 to 76 degrees Celsius and166 to169 degrees Fahrenheit. The employees were standing 8 to 10 ft from the front of the IBC tote. Over pressurization caused the lid of the IBC tote to open its seal and hot water went into the air and sprayed down on Employees #1, #2, and #3. The employees were able to turn away prior to being burned by the water. Employee #1 suffered first and second degree burns on his back. Employee #2 suffered first and second degree burns along his back to his upper buttocks area. Employee #3 suffered second and third degree burns on the back of his right arm, neck, ears, and the back of his head and along the entirety of his back. The employees were placed under chemical and lab showers by members of the sites emergency response team and were taken to Riverview Occu-Med Hospital, where they were treated for burns. The employees were later transported to the Burn Center at the Chapel Hill Hospital and to the Burn Center at CMC in Charlotte, North Carolina. Employees #1, #2, and #3 remained hospitalized.