One of the ergonomic issues faced by operators in the hydro-vac industry is the use of the dead-man trigger, which requires the operator to assume a static posture by holding the trigger above shoulder height while cutting the ground with the nozzle. This posture can lead to shoulder injuries over time, which is a commonly reported type of injury among hydro-vac industry workers and is among the leading injury types recorded by WSIB.
Why not just remove the deadman trigger…..
The TSSA Excavation guideline mandates the use of a deadman trigger as a means to stop the excavation on demand. This requirement was put in place after a fatal incident that occurred on August 26, 2017.
Description of Fatal Incident
A worker was operating a hand-held remote for the hydrovac truck as well as the jetting wand. At one point, the worker held the flexible part of the hose to allow the wand to get into a deeper area of a drain. He lost control, dropped the hose, and was killed when the water jet hit him in the neck.
Due to the mandatory use of the dead-man trigger, assuming a static posture with arms elevated above shoulder height can lead to a range of ergonomic concerns. This posture can result in muscle fatigue, discomfort, and pain in the neck, shoulders, arms, and back. Over time, holding the arms in a static posture can increase the risk of developing musculoskeletal disorders (MSDs) such as shoulder tendinitis, rotator cuff injury, and bursitis. This type of static posture can also lead to decreased blood flow and nerve compression, which can result in numbness and tingling sensations in the arms and hands.