Worker had a false sense of security while entering tank

Incident summary: A worker had a false sense of security while entering a dangerous tank because his oxygen meter didn’t go off. That’s because the primary hazard inside the confined space was a toxic gas.

The damage: A two-person work crew was assigned to clean the inside of a storage tank. The tank hadn’t been cleaned in quite some time, and it contained a higher-than-normal level of animal residue.

The plan was to lower a fan into the tank from above in order to ventilate it and to then descend into the confined space to clean it.

However, it was difficult to get the fan into the tank, so one crew member grabbed an oxygen meter and climbed down the ladder into the confined space. Because his oxygen meter didn’t sound, he didn’t think he needed to put on a self-contained breathing apparatus (SCBA) even though there was one available for his use.

When the staffer reached the bottom of the ladder, he stepped into the residue and called out to his crew mate, “There’s no air here.”

He began to climb up the ladder, but he quickly lost consciousness and fell face- first into the animal residue.

It took about 20 minutes for two rescuers equipped with SCBAs to reach the victim and to pull him from the tank. However, he’d already inhaled lethal levels of the hazardous gas.

Findings: If the workers had been trained on the dangers of confined spaces, they would’ve realized that decayed animal residue can lead to the formation of a deadly gas.

And they would’ve known that the oxygen meter was of no value because they needed a gas detector. If anything, the oxygen meter provided a false sense of security, noted investigators.

(From the Feb. 16, 2021, issue of Safety Alert for Supervisors. To start a no-obligation trial subscription to the publication, please click here)