Abstract: At approximately 11:30 a.m. on August 11, 2006, Employee #1, a truck driver with Hills Brother Chemical Company, was delivering aqueous ammonia to the City of Escondido/ Vista Water Treatment Plant. He opened the cam lock on his tanker truck's main liquid delivery line. The pressured aqueous ammonia residue within the delivery line sprayed onto his groin and upper thigh. After Employee #1 moved from the spill area, a coworker rinsed his clothes and skin with water from a nearby hose. After Employee #1 began to experience some discomfort and irritation to the affected areas, he sought treatment at Polomar Medical Center. Employee #1 was later transferred to the University of California, San Diego (UCSD) Burn Center, where he obtained additional treatment for the chemical burns.