On December 19, 2007, T2 Laboratories suffered a massive explosion, killing four people and injuring 32. Debris was found up to one mile away. The facility was destroyed. There were severe environmental consequences, as toxic chemicals were released into the air and nearby waterways.
The root cause of the explosion, according to the U.S. Chemical Safety and Hazard Investigation Board's investigation, was the company's failure to identify the runaway reaction hazards associated with its chemical product, a gasoline additive. When T2 Laboratories developed the MCMT chemistry, it was based primarily on patents granted in the late 1950s and early 1960s. The CSB found no published information about the reactivity hazards of MCMT.
“A lack of available process hazard information makes laboratory testing especially important,” (CSB Investigation Report T2 Laboratories, Inc. Runaway Reaction, p. 26).
Chemical reactivity hazards have been the cause of many deadly accidents in the chemical industry. This article explores how experimental hazard evaluation of chemicals can help uncover unknown hazards, which is essential for preventing unexpected responses and mitigating risks. Specialty chemical companies, contract developers, manufacturing organizations, and toll manufacturers will find this particularly helpful.
T2 Laboratories was a small chemical company specializing in the production of gasoline additives and other chemical compounds. The fatal incident took place in their facility, located in an industrial area in Jacksonville. The reaction involved the production of methylcyclopentadienyl manganese tricarbonyl (MCMT), a gasoline additive, in an exothermic reaction that also produces hydrogen. The process was designed around a 1-liter reactor, which was scaled up directly to a 2,500-gallon reactor. After 41 batches, T2 Laboratories increased the reaction load by an additional third. During subsequent runs, unexpected temperature rises occurred.
On the day of the incident, cooling water could not be sent into the jacket of the vessel possibly due to a blocked supply pipe or valve failure, resulting in an uncontrolled rise in temperature and pressure in a runaway reaction. The owners of the facility were called, and when they arrived, they told employees to move away from the reactor. The pressure continued to build, eventually bursting the rupture disk. Ten seconds after the disk burst, the vessel exploded.
This explosion was extremely powerful, causing widespread damage to the facility and nearby structures. The blast wave shattered windows, collapsed roofs, and sent debris flying over a significant area. The shockwave was felt several miles away from the site, and the resulting fire burned for hours.
The CSB investigation reported two contributing factors: (1) No redundancy in the cooling system and (2) the pressure relief system was not sized for a runaway reaction. This is clearly a case where additional chemical reactivity information may have prevented this tragedy.
The system was tested in a one-liter glass reactor up to 380°F. During the start-up phase, there were many near misses, suggesting that runaway exothermic reactions were possible. The rupture disk was sized for normal operations, not expected failures, at 400 psig. The vessel MAWP was 600 psig.
During their investigation, the CSB conducted reactivity testing of the normal process mixture, molten metallic sodium, methylcyclopentadiene (MCPD), and diethylene glycol dimethyl glycol dimethyl ether (diglyme) and a combination of two of the reactants (sodium and diglyme).
The graph below shows a calorimetry trace from the normal process mixture test. This plot shows that the desired reaction mixture if allowed to increase in temperature, will result in a dangerously high reaction rate of 2340°F and a pressure generation rate of 32,000 psi/min. In the test, this reaction burst the test vessel. Before failure, pressures of 1788 psig were measured at a temperature of 1222°F.
Temperature and pressure vs time data, (CSB Investigation Report T2 Laboratories, Inc. Runaway Reaction, p. 59)
A review of the laboratory data shows:
According to the incident report, the CSB found no evidence that T2 Laboratories ever performed a hazard and operability study (HAZOP). By conducting a thorough Process Hazard Analysis (PHA) of the reaction incorporating chemical reactivity testing as part of its analysis, the facility would have known what appropriate safety measures needed to be implemented. The data would have identified the need for multiple controls:
The ioKinetic laboratory has many instruments for conducting chemical reactivity testing, including thermogravimetric analyzers (TGs), differential scanning calorimeters (DSC) and the Accelerating Rate Calorimeter (ARC®), and low phi-instruments, such as the Vent Sizing Package (VSP) and the Automatic Pressure Tracking Adiabatic Calorimeter (APTAC™). Chemical reactivity testing will assist you in reducing hazards that you may otherwise not be aware of, and help you comply with regulatory standards.
By using experimental analysis methods, it is possible to uncover unknown hazards. This allows for the analysis of prevention and mitigation methods to prevent unwanted reactions and mitigate their effects should they occur. Each reaction system is unique and the effects of process and chemical variables cannot always be predicted using theoretical analysis alone. As we develop and improve our chemical processes, experimental hazard analysis is another tool to help keep us safe.
The professionals at ioKinetic will work with you to determine the level of analysis that is required for your particular needs, we'll maximize efficiency by eliminating unnecessary testing without compromising safety, and we'll answer all your questions to help you stay safe. Request your free quote today or call us at 1-844-ioKinetic.
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