Risk Assessment on Storage and Handling of Highly Toxic Chemical in Rocket Industry

Abstract

In solid propellant manufacturing of the rocket industry, many chemicals are used, but among all Toluene di-isocyanate (TDI) is highly toxic and also recently the threshold limit value (TLV) was amended from 0.005 to 0.001 ppm by American Conference of Government Industrial Hygienists (ACGIH). The exposure to TDI occurs mainly through inhalation of vapors at workplace and storages; hence, TDI is to be carefully handled due to its toxic nature which affects human health and environment; therefore, spillage of Toluene di-isocyanate causes adverse effects, so utmost care should be taken to avoid human exposure to the toxic vapors. Due to industry demand, in processing of solid propellant, large quantity of TDI was used as curator, which will be in the form of containers stored in bulk in designated storage rooms of the order 8–16 tons. Any major spillage/leakage in this store may affect the plant personnel as well as nearby residential area people in this paper; we evaluated the TDI evaporation rate and concentration level at residential area locations by ALOHA software and as per the Acute Exposure Guideline Level (AEGL) or Emergency Response Planing Guidelines (ERPG), and by this, we found that at 5000 m no significant concentration. At the same time, for the processing of solid propellant, various methods of TDI handling require the usage of different types of valves, hoses, and pipe fittings. Further, the failure modes of these handling components can lead to TDI spill/leakage and evaluated the exposure concentration level for that spills by using different hazard identification techniques. With the results, we conclude that the concentration is within the acceptable range by applying risk control measures.