Hydrogen Sulfide Gas Inhalation (KV124)


What Happened?

At 11:45 p.m. on May 31, 2017, an employee was cleaning a tanker truck. The employee passed out after inhaling hydrogen sulfide gas released from the tanker. The employee fell approximately 10 feet from the top of the tanker to a concrete floor. The employee sustained a fractured skull, fractured vertebrae, fractured shoulder, and bleeding.

Contributing Factors

Toxic hydrogen sulfide gas.

What Can We Learn?


By using a Questioning Attitude, the employee would have considered the consequences of his actions if performed with a tank full of hydrogen sulfide. 

By following Procedures, the employee would have checked to ensure the tank was safe to clean.


Overconfidence caused the employee to overestimate his knowledge, underestimate risks, and exaggerate his ability to control events. 

The Physical Environment was not safe for the employee to complete his work.

Ask the Right Questions

How does this relate to our work?

Where do we have similar traps?

What Tools can we use to avoid a similar incident?

Was a stop work point missed?