Abstract: At 10:45 a.m. on February 28, 2017, an employee was working for a firm engaged in commercial and institutional building construction. He was at a job site, and there was a section of mezzanine approximately 1.0 meters wide by 2.4 meters long (40 inches wide by 8 feet long) at the site. It had been pre-cut for removal. It was held in place by approximately 11 existing welds. The employee went up onto the mezzanine to remove guardrail components. Fall protection equipment had been installed and was available for use. The employee had not connected his harness to it. He picked up a guardrail base to remove it from the work area. It weighed approximately 32 kilograms (70 pounds). He then inadvertently stepped onto the pre-cut section of the mezzanine surface. The section welds did not hold. The pre-cut section fell approximately 3 meters (10 feet) to a lower surface level, with the employee landing on top of it. He sustained a fractured hip and elbow and he was hospitalized.