Explosion at a Rubber Factory, Caused by Accidental Hydrolysis of Chemicals
At a rubber factory, an explosion occurred inside a lubricant container filled with 18 tonnes of tri-(nonylphenyl) phosphite (TNPP or TNPA). This tank was typically stirred and maintained at 45C. However, the heating circuit routed to the container had broken down 7 days earlier. With the polluted TNPP scheduled for disposal, the accident occurred during a sawing operation to remove the walkway interfering with the manhole opening. The TNPP substance underwent hydrolysis in contact with water leaking via the broken coil; the resultant phosphoric acid corroding the steel on the container caused hydrogen to form. The relatively slow hydrolysis reaction was no doubt catalysed by metal particles (rust, etc.). A technician was seriously injured due to a fall.
Event Date
August 10, 1999
Record Quality Indicator
Region / Country
Event Initiating System
Classification of the Physical Effects
Nature of the Consequences
Cause Comments
Immediate cause: the release of TNPP substance which underwent hydrolysis in contact with water leaking via the broken coil with consequent formation of hydrogen. Ignition very probably was catalyzed by metal particles (rust, etc.).
Facility Information
Application Type
Application
Specific Application Supply Chain Stage
Components Involved
a lubricant container filled with tri-(nonylphenyl) phosphite (TNPP or TNPA)
Location Type
Location description
Industrial Area
Pre-event Summary
This tank was typically stirred and maintained at 45C; however, the heating circuit routed to the container had broken down 7 days earlier. The accident occurred during a sawing operation to remove the walkway interfering with the manhole opening. The sawing operation was aiming at disposing polluted TNPP.
Lessons Learned
Lessons Learned
Implemented recommendations: 1. To ventilate the installation and protect it from rainfall or any other potential water intake, 2. To install concentration detectors 3. To train personnel.4. To replace the hating coil with a heating belt (with Tmax T of TNPP degradation) 5. To post instructions to remind workers of the product's sensitivity to water.
Event Nature
Emergency Action
Unknown
Emergency Evaluation
A heating belt (with Tmax T of TNPP degradation) replaced the coil, and a posted instruction reminded workers of the product's sensitivity to water.
Detonation
No
Deflagration
No
High Pressure Explosion
No
High Voltage Explosion
No
Source Category
References
References
ARIA data base
event no. 16467