Several employees of Tagoor Laboratories, JNPC, Parawada were exposed to a toxic gas release in the early hours of 27 November 2024 but were not shifted to any hospital for about 6 hours. This exposure caused the death of two workers and the hospitalization of 29 to date. One worker’s condition is critical. There are 27 persons undergoing treatment at hospitals now. Most likely the two victims were close to the manhole when exposed.
The information given in the press refers to the release of hydrogen chloride while mixing Hydrochloric acid with chloroform. It may be noted that Hydrochloric acid and chloroform are immiscible and do not react. Our inquiries reveal that triphosgene, a solid powder, was being dissolved in chloroform in preparation for the synthesis of the first stage raw material for lamivudine production.
Likely, the chloroform used was not free of water (It can contain 0.8% of water at room temperature) or contained any alcohols, amides, Amines, ferric oxide, and alkaline capable of decomposing tri-phosgene.
These contaminants could be responsible for the decomposition of tri-phosgene to phosgene. This is yet another example of open feeding of solids through a manhole (At Synergene fire and explosion were due to that) instead of closed feeding to avoid any exposures and releases. In the eventuality of any toxic gases released during feeding, these should be directed to a scrubber or incinerator for removal. These are part of an inherently safe design missing from our industries. Authorities investigating the accident should look into the presence of contaminants that caused the decomposition of tri-phosgene.
Normally, triphosgene dissolution involves heating the kettle with hot water. If the hot water temperature is too high, tri-phosgene is decomposed to produce highly toxic gases such as phosgene. The presence of impurities (such as organic amines) can lead to the decomposition of tri-phosgene. All these possibilities should be checked and the actual cause identified.
Permissible Exposure Limit (PEL) for phosgene is 0.1 ppm for OSHA. “The odor threshold for phosgene is 5 times higher than the OSHA PEL. Thus, odor provides insufficient warning of hazardous concentrations.” Exposure happens without knowing. Only after symptoms of exposure manifest can one realize the harm.
Immediate Danger to Life and Health (IDLH) value for Phosgene is 2 ppm.
Exposure to phosgene at 5 ppm for 30 minutes could be fatal.
Hydrogen chloride: Acute exposures of hydrogen chloride beyond the IDLH value of 50 ppm could be fatal. However, the effects of HCl are immediate and localized. The effects of exposure are not delayed.
Phosgene: As per the information provided by “Agency for Toxic Substances and Disease Registry” (ATSDR) USA “Phosgene is a severe pulmonary irritant. However, serious pulmonary effects may be delayed up to 48 hours.”
“Phosgene has relatively little odor or irritating effects at moderately toxic air concentrations; serious health effects may occur without warning or symptoms. Because serious complications may be delayed up to 48 hours after exposure, all patients who have suspected phosgene exposure should be transported to a medical facility for evaluation.”
“There are no tests to positively determine whether you have been exposed to phosgene. If you suspect that you may have been exposed to phosgene, a chest X-ray may be the quickest way to determine if your lungs have been damaged.”
Admitting 18 workers more in the hospital on 28.11.2024, nearly two days after the exposure points to the fact of low phosgene exposure. The company has been hiding the truth and misinforming the public. Regulatory officials as usual abandon the people and promote the story fed by the offending company. These officials have not questioned the false information being spread through the media. What protections can people expect from such a system?
Dr K Babu Rao,
Scientist For People.
K. Anuradha,
Human Rights Forum
29.11.2024