On July 14, at around 3 am, a leak from a chlorine container in the Mumbai Port Trust premises in the suburb of Sewri triggered panic in the nearby areas. Over 120 people complained of difficulty in breathing and eye irritation after exposure to the pale greenish-yellow gas. Those affected belonged to the nearby Lal Bahadur Shastri College of Maritime and Research Studies, fire-fighters and port workers. There were no casualties.
The gas leak was controlled before it could cause further damage. But the incident exposed how ill-equipped the state governments are to handle chemical leaks and disasters; rules and regulations for management and disposal of hazardous wastes remain on paper.
Preliminary investigations revealed the port had over 140 large canisters in the premises, lying as unclaimed cargo since the late 1990s. Authorities found that there were at least six canisters, including the one that leaked, filled with chlorine gas; the rest were empty. Each cylinder weighed about a tonne. In spite of repeated warnings from the fire brigade, the port authority had not bothered to neutralise the gas in the canisters and dispose them safely. People were lucky only one of the containers had leaked. High concentrations of the gas can be lethal (see: Chlorine can be toxic). Mumbai Port Trust (MbPT) launched an enquiry into why the cargo was left unattended following orders issued by the Union shipping ministry. The report was submitted to the Prime Minister during the cabinet meeting on July 15.
Initial reports suggest these containers were imported by Agro Gases Pvt Ltd in 2001 and were abandoned by the importer as he failed to clear customs duties. Since then these containers are lying unattended at the port premises. About six years ago, the containers were shifted from a warehouse to a corner of an open yard. Over the years, they corroded; one of them developed a leak on July 14.
MbPT and customs authorities are blaming each other and the Department of Explosives in Nagpur. MbPT claimed it could not get rid of the containers without permission from the customs and the chief controller of explosives. Rahul Asthana, chairperson of MbPT, told media that he had sent a letter in 2008 seeking permission from to get rid of the cylinders, but the chief controller of explosives did not respond. Customs officials said MbPT should not have waited for their permission for disposing the hazardous gas containers.
Under normal circumstances, if nobody claims an imported consignment for 30 days, the MbPT, becomes the guardian or importer, by default. It then brings out tenders and auctions the consignment. This process takes about a year. After auction, the MbPT pays the customs duty from the auctioned amount and keeps the remaining money.
The recent incident has also highlighted the problem of jurisdiction. Soon after the gas leak, the fire brigade and the local municipal body were called to neutralise the cylinders, but both the agencies do not have any jurisdiction over MbPT because ports come under Centre's jurisdiction.
A similar incident was reported on July 15 at Durgapur in West Bengal where 25 workers fell sick after carbon monoxide and methane leaked from a blast furnace of Durgapur Steel Plant.
Chlorine can be toxic
Chlorine is an irritant gas and used in making a variety of everyday products. It is extensively used in the production of paper products, dyes, textiles, petroleum products, medicines, antiseptics, insecticides, food, solvents, paints, plastics, and many other consumer products. Most of the chlorine produced is used in the manufacture of chlorinated compounds for sanitation, pulp bleaching, disinfectants, and textile processing. It is an essential reagent in the chemical industry.
It is also a toxic. It irritates the eyes and the respiratory system. Because it is heavier than air, it tends to accumulate at the bottom of poorly ventilated spaces. Chlorine gas is a strong oxidizer, which may react with inflammable materials.
Chlorine is detectable in concentrations of as low as 0.2 parts per million (ppm). Coughing and vomiting may occur at 30 ppm and lung damage at 60 ppm. About 1000 ppm can be fatal after a few deep breaths of the gas. When chlorine is inhaled at concentrations above 30 ppm it begins to react with water and cells which change it into hydrochloric acid and hypochlorous acid.