Abstract: At 8:00 a.m. on November 8, 2018, Employee #1 was performing mechanical support duties. The accident involved a Decontamination Module, Identified by the Employer as KA30011. Employee #1 was assigned to change metal plates (15 inch by 2 inch, approximately) located inside the Denomination Unit, a permit-required confined space. Employee #1 gathered the tools needed to replace the metal plates and climbed up to the location of the confined space entry. The employee went through the 18 inch (approximately) opening and began descending the 16 rungs (approximately) ladder, into a unit containing nitrogen gas. Consequently, within 3-5 seconds (approximately), Employee #1 lost consciousness due to the oxygen-deficient atmosphere and fell over 10 feet below. Soon after, Employee# 2, went through the opening and began to descend the ladder when he suffered the same effects and fell onto Employee# 1. Employee# 1 and Employee# 2 were transported to LAC + USC Medical Center,where they were treated for their injuries.