A worker and his co-worker were carrying and installing solar panels on the roof of a warehouse. The roof contained skylights that were marked by the manufacturer as "TESTED" in accordance with OSHA fall protection standards. However, there are currently no test criteria to determine the material strength of skylights to withstand worker impact. The GC reviewed the job and established a safety program. Based on the information that the skylights had been tested, no other fall protection measures were implemented at the job site. Each panel was approximately weighed 20 pounds. The worker and co-worker were carrying two or three panels at a time. As they approached the skylight, they had to maneuver around it with very little clearance. The worker turned and walked backward, tripping on the raised edge of the skylight. He landed on the skylight and fell through it. As the worker started to fall, his co-worker tried to grab his leg but was unable to reach him in time. The victim fell down to the warehouse floor below. The supervisor called the emergency immediately and called the office to report the incident.

a) What are the reasons which lead up to this casualty?

b) In terms of Project Monitoring for Quality Control and Safety, how could this be prevented?