This past week we witnessed a tragic incident involving chlorine (Cl2), a 25-ton ISO container, and a crane/sling failure. The incident claimed 13 workers’ lives and sent another 250 to hospitals for emergency care. Many have claimed this to be the “worst-possible outcome”. Here in the USA, we call these “Worst Case Release Scenarios” (WCS). A lot of process safety and OSH professionals have a distorted view that a WCS scenario can’t happen in 10-minutes as defined by the WCS definition. Well, we just got to witness a catastrophic release that was 20-25 tons of liquefied Cl2 in under 10-minutes. A Liquified-Pressurized Gas (LPG – not to be confused with Liquified Petroleum Gas). OSHA defines a Liquefied [Pressurized] Gas as:
A gas that when under pressure is partially liquid at temperatures above -58°F.
A distinction is made between:
(a) High pressure liquefied gas: a gas with a critical temperature between -58°F and 149°F; and
(b) Low pressure liquefied gas: a gas with a critical temperature above 149°F.
The “critical temperature” is the temperature above which a pure gas cannot be liquefied, regardless of the degree of compression.
If this incident was not enough to validate the RMP WCS model, imagine if the crane failure had occurred when the 25-ton container was traveling over these:
Highlighted by the yellow box are dozens of other Cl2 ISO containers. Imagine if this dropped container had impacted one of these other containers and BOTH containers received catastrophic damage and we had a 40-ton Cl2 release. Loading and Unloading HAZMATs is by far the greatest risk that some businesses will have on-site and many never blink an eye at it and try to make the case that “it is outside” the window of compliance requirements.
The red arrow is where the container landed, made contact with a protruding object, punctured the shell of the pressure container, flipped end-over-end, and landed where is shown. The green box is the crane that was lifting it.
