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1. Waukegan, Illinois, USA, 03-May-2019
4 employees fatally injured by H2 Fire
and Explosion
Hydrogen Release
at AB Specialty
Silicones
Source: CSB Final Investigation Report No. 2019-03-I-IL, published on September 24, 2021 in www.csb.gov
LebSolution Safety Moment
What Happened:
During production using batch operation, an incorrect chemical
was pumped into the tank. This chemical is incompatible with
another chemical that was added to the tank before. The
incorrect chemical and the correct chemical were stored in an
identical drum and the only differentiating marks are small
labels and bung caps.
Once the chemicals were mixed and reacted, they produced
foam and overflowed from the tank. After a while, fog is
formed containing flammable H2 gas. The H2 gas was trapped
inside the production building and was immediately ignited,
causing a massive fire and explosion.
CONSEQUENCE
4 Personnel fatalities and
Building Destruction
HAZARD
Mixing of
Incompatible
Materials UNDESIRED EVENT
Two incompatible chemicals
react and produce
flammable Hydrogen (H2)
gas.

2. 2
Hydrogen Release at AB Specialty Silicones
How It Happened:
• Storage of Incompatible Materials is the same as the compatible ones. The only differentiating marks are small labels and bung caps.
• Lack of an effective hazard analysis program. They didn’t identify the hazards associated with (1) storing reactive chemicals in similar
containers, (2) the practice of allowing incompatible materials to be stored near each other, etc.
• Batch Equipment and Ventilation System Design. The tanks used for the batch process didn’t have a vent pipe to direct gases to a safe
location and the ventilation system at the production building was designed to introduce outside air to the building and may help the H2 mixing
with air.
• Gas Detection and Alarm Systems were not available.
• Emergency Preparedness. During the incident, workers recognized the process upset occurred. However, they didn’t realize that there is H2 gas
formation from the unintended reaction and also there were no gas detectors and alarms to warn them to evacuate.
• Process Safety Culture. Lack of engineering controls to mitigate employee exposure to potential hazards
• Safety Management System that Addresses Process Safety. Process Safety Management system is not implemented, while the facility has
potential reactive chemical hazards.
• Regulatory Coverage of Reactive Hazards. The chemicals used in AB Specialty are not listed in OSHA PSM Standard or EPA EMP Rule, then
there wasn’t any requirement to implement the PSM system.
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