Did English Chemical Label Lead to Chlorine Gas Leak?

In an Associated Press article today, Kelly P Kissel reported that a CDC report claims last year's Tyson foods chlorine gas leak, which sickened nearly 200 people, was triggered by a worker who could not read the English-language label on the empty chemical drum into which he poured sodium hypochlorite (a bleach). The drum, according the article, contained a residual solution of acidic antimicrobial agent, which mixed with the bleach to create chlorine gas.

In the United States, under the Hazard Communication Standard (HCS), hazardous chemical containers are required to have a label in English. Other languages are permitted in addition to English, though not required. Employees on the other hand are required to be trained on chemical hazards in the workplace in a language they understand.

OSHA recently revised its HCS to align with the Globally Harmonized System (GHS), with a primary goal of improving hazard communication, especially on labels. Labels under GHS have new and standardized elements, like pictograms (hazard symbols that communicate chemical hazards visually) --  however it is uncertain at this time whether updated labels in the GHS format would have prevented an accident like the one at Tyson foods.

Kissel reports that the CDC commented, "All communication, training, and signage in the workplace should be easy-to-read and provided in languages understood by workers." That statement, while making sense, would go beyond the compliance directives issued by OSHA.

Tyson food for its part says the CDC investigation got it wrong and that the worker in question is an English speaker who was trained on chemical hazards and just failed to read the label.