Abstract: At approximately 5:15 a.m. on November 13, 2003, Employee #1 submerged the spherical unit, MOT part Number 2341591-1, at Station 4 of Work Cell 5 in a water tank designed to protect against explosion to check for air leaks. He then pressurized the unit with nitrogen to 244 psi. Shortly after that a coworker heard the motor of the tank's lift arm as Employee #1 raised the unit above the water, upon which the clarifier exploded, with part of the debris striking Employee #1 on the left side of the head. He suffered a severe left side head injury from an exploding ozone clarifier, a 20-inch-long football- shaped inconel part placed partway along a pilot's air supply line to remove ozone, during a pressurized test. Employee #1 was taken to UCLA Harbor General Hospital in extremely critical condition on life support.