Abstract: At 9:39 p.m. on April 12, 2011, Employee #1, a regular fulltime employee, was working at the Calipatria State Prison, in Calipatria, CA. The prison, which had been in operation since 1992, housed almost 3,000 inmates and had a staff of 12,000 fulltime, regular employees. Its mission was to protect the public by providing safe custody, quality health care, and the appropriate supervision of sentenced offenders. Employee #1 fell down a stairwell of Tower Number 5, while carrying his rifle and ammunition. Employee #1 apparently bruised and/or abraded his back, and he was hospitalized. At 3:24 p.m. on April 13, 2011, an employer representative telephoned the Division to report the serious injury, within required time limits.