Abstract: On September 26, 1999, Employee #1, Employee #2, and Employee #3 were participating in a training drill. All three employees were assigned to the decontamination team, which is responsible for decontaminating hazardous materials response members. The team was suited in level B protective gear and was utilizing Self Contained Breathing Apparatus. The team was using a "buddy breather" system, which allowed the team to switch from breathing air from a cylinder to an airline drawing air from Air Utility-21 air tanks. The Air Utility-21 airline system consisted of 300 ft of Synflex hose (an internal part of system), a manifold, and three separate 75-ft portable Gates Premoflex airline hoses. The manifold was capable of splitting the compressor's airlines into five 50-ft lines; however for the purpose of this drill, three 75-ft lines were used. Employee #1 was the first of the three team members to switch to breathing air from the Air Utility-21 airline. Employees #2 and #3 switched onto the airline a few seconds later. Employee #1 reported that after approximately 10 seconds, he began to feel dizzy. Employee #1 stopped and bent over to rest and informed Employees #2 and #3 to suit-up. Employee #1 recalls walking away from Employee #2 and #3, stumbling and tripping. Employee #1 then fell, face-forward, onto the floor, but does not remember this. The impact of Employee #1's fall resulted in a laceration to his nose and forehead caused by the impact of his face hitting his respirator face piece. This injury required stitches. The next thing Employee #1 remembered was being aware of firemen picking him up and providing him with first aid. Employee #2 connected to the airline after Employee #1. Employee #2 recalls that after approximately two breaths, he began to feel dizzy and thought that he may have stood up to quickly which he reasoned was the cause of his dizziness. After a dozen more breaths, Employee #2 felt lightheaded, nauseated, dizzy, and had hazy vision. Employee #2 then looked towards Employees #1 and #3 to see what they were doing and disconnected himself from the airline. Employee #2 took a few steps towards Employee #3 and yelled at him to "go off air." Employee #2 then realized Employee #1 was down on the floor. Employee #3 switched over to breathe air off of the airline shortly after Employee #2. After one or two breaths, Employee #3 recalls having difficulty with his manual dexterity, having a hard time attaching a hook that holds his breathing apparatus, and felt that he had tunnel vision. After approximately 10 seconds of breathing air from the airline, Employee #2 yelled at him to disconnect himself from the airline. Employee #3 disconnected from the airline, estimating that he had breathed air from the line for no more than 15 seconds. At this time, he noticed that Employee #1 was on the ground. Paramedics were present at the drill and took the vitals of all three team members and placed them on oxygen for 20 minutes. All three employees were then taken to the hospital and treated but not hospitalized.