Monday, August 29

Bhopal Disaster- Chemistry

Methyl isocyanate (MIC), a chemical, leaked from a pesticide facility owned by Union Carbide India Ltd. (UCIL) on December 2, 1984, turning the city of Bhopal into a massive gas chamber. India's first significant industrial tragedy. More than 600,000 workers were harmed and more than 15,000 individuals died as a result of at least 30 tonnes of methyl isocyanate gas. The Bhopal gas tragedy is regarded as the greatest industrial accident in history.

What caused the methyl isocyanate leak?

Three 68,000-liter liquid MIC storage tanks were located in Union Carbide India's Bhopal facility: E610, E611, and E619 MIC manufacture were underway and the tanks were being filled months prior to the accident. Each tank was pressurized with inert nitrogen gas and could not be filled more than 50% of the way. Each tank's liquid MIC might be blasted out thanks to the pressurization. However, one of the tanks (E610) was no longer able to withstand the pressure of nitrogen gas, making it impossible to pump liquid MIC out of it. Each of the tanks could hold no more than 30 tonnes of liquid MIC in accordance with the regulations. However, this tank weighed 42 tonnes. Due to this incident, UCIL was compelled to stop producing methyl isocyanate at Bhopal, and the plant was partially shut down for maintenance. On December 1, an attempt was made to repair the broken tank, but it proved unsuccessful. By that time, the majority of the safety systems at the factory that dealt with methyl isocyanate were broken. According to sources, water entered the failing tank on December 2 eve, causing a chemical reaction to go out of control. By night, the tank's pressure had multiplied five times. The effects of the MIC gas on the workers in the MIC region began to manifest by midnight. A few minutes later, the decision was made to stop the leak. The chemical reaction in the tank had, however, already reached a critical stage at that point. Within one hour, about 30 tonnes of MIC broke free from the tank and into the atmosphere. The majority of Bhopal people were exposed to the gas, which alerted them to the leak.

An alarm sounds before a calamity

Methyl isocyanate was used as an intermediary in the production of Sevin, a pesticide, at the UCIL factory in 1969. Trade unions in Bhopal raised concerns about contamination inside the facility in 1976. A few years later, a worker died a few hours after unintentionally inhaling a significant amount of poisonous phosgene gas. A journalist who was seeing the occurrences started looking into the facility and then published his findings in the local Bhopal newspaper with the headline "Wake up citizens of Bhopal, you are on the edge of a volcano." About 45 workers who had been exposed to phosgene were admitted to a hospital two years prior to the tragedy in Bhopal. There was leakage of phosgene, carbon tetrachloride, methyl isocyanate, and mono methylamine between 1983 and 1984.

To Read About: The Three Mile Island nuclear disaster

Effects of a leak of methyl isocyanate

The incident's correct treatment options were not known to the doctors. More than 600,000 workers were affected and over 15,000 individuals died as a result of the methyl isocyanate gas leak. Neonatal mortality and the stillbirth rate both rose by up to 300% and 200%, respectively. Trees and animals are also affected by gas leaks. The neighboring trees quickly become barren within a few days. Animal carcasses that were bloated had to be discarded. In the streets, people fled while throwing up and dying. The city's supply of crematoriums ran exhausted.

GOVT's response to the disaster in Bhopal

The Indian government had never before faced such a catastrophe. Immediately following the disaster, legal processes between India, UCC, and the US were initiated. In order to advocate victims' interests in court, the government passed the Bhopal Gas Leak Act in March 1985. The UCC initially offered India a $5 million assistance fund, but the government rejected it and requested $3.3 billion instead. In the end, a settlement outside of court was struck in February 1989, and Union Carbide agreed to pay $470 million in losses. The Supreme Court of India also established rules for the money, mandating that the deceased's relatives get between Rs 100,000 and Rs 300,000. Additionally, individuals who were totally or partially incapacitated were to get between Rs 50,000 and Rs 500,000, while those who had a temporary injury were to receive between Rs 25,000 and Rs 100,000. The top court urged UCIL to "voluntarily" support a hospital in Bhopal to care for the tragedy's victims. Seven former UCIL employees, all of whom were citizens of India, were found guilty of causing death by carelessness and given two years in prison in June 2010. They were eventually released on bond, though. Bhopal following the catastrophe of more than three decades.

UCC was successfully taken over by Dow Chemical Company in 2001, and as the legal disputes between India and the US continued, it became a wholly-owned subsidiary. Then, according to Dow, UCC was legally a new firm with new ownership and had no involvement in the catastrophe. Ingrid Eckerman quotes a sufferer as saying, "Death would have been a wonderful comfort," in his book The Bhopal Saga. To be a survivor is worse. There has been no resolution to the lawsuit thirty years later. Numerous survivors of the Bhopal gas disaster still struggle with a shortage of medical resources. Whatever was left inside the factory after it was shut down was sealed and stored there. Welfare organizations representing gas victims have been requesting its removal for years. There are numerous applications pending before the SC and high court to get the plant's poisonous leftovers removed.

What is MIC, or methyl isocyanate?

A colorless liquid called methyl isocyanate is used to create insecticides. When maintained properly, MIC is safe. The substance reacts with heat quite quickly. The chemicals in MIC interact with one another when exposed to water, producing a heat reaction. Although it is still used in pesticides, methyl isocyanate is no longer produced. The sole MIC storage facility that remained in existence today is at the Bayer CropScience facility in Institute, West Virginia.

Effects of methyl isocyanate chemical reaction on health

Ulcers, photophobia, respiratory problems, anorexia, chronic stomach discomfort, hereditary conditions, neuroses, decreased hearing and vision, impaired reasoning, and many other conditions are among the immediate health impacts. Chronic conjunctivitis, diminished pulmonary function, increased pregnancy loss, higher newborn mortality, increased chromosomal abnormalities, poor associative learning, and other conditions are long-term health impacts.

To Read About: Chemical Plant Explosions – 2005, Jilin

Sunday, August 28

Bleaching Powder [ Bleach-Chemistry]

Bleach is a solid or liquid chemical that is used to lighten or take away the natural color of paper, textiles, and other fibers. The bleaching procedure is used in textile finishing to create white fabric, to get materials ready for additional treatments, or to get rid of discoloration that has happened in previous procedures. Because of its microbicidal qualities, bleach is also employed as a disinfectant. As bleaches, people frequently utilize chlorine, sodium hypochlorite, calcium hypochlorite, and hydrogen peroxide. Bleaching powder is basic in character. It gives calcium chloride, chlorine, and water when bleaching powder reacts with hydrochloric acid.

An inorganic compound having the formula Ca(OCl)2 is calcium hypochlorite. It is the primary component of commercial bleaching powder, chlorine powder, and chlorinated lime products, which are used to treat water and as bleaching agents. Compared to sodium hypochlorite, this chemical is more stable and has more chlorine that is readily available. Despite the yellow appearance of commercial samples, it is a white solid. Due to its slow degradation in damp air, it has a strong chlorine odor. T.C.L. powder is another name for bleaching powder. Simply put, beaching powder is a mixture of lime and chlorine.

Fresh bleaching powder often contains 33% or more chlorine. Since bleaching powder is inherently unstable, its chlorine content decreases over time. Bleaching powder needs to be stored dry and out of direct sunlight in order to prevent chlorine loss. If the bleaching powder is packaged in a bag, it must be properly closed after use.

A laboratory test can determine the amount of chlorine present in the bleaching power.

When a very small amount of diluted acid is present, the bleaching powder reacts, releasing newly formed oxygen. The bleaching powder functions as both a bleaching and an oxidizing agent as a result of the release of the nascent oxygen.

The process of making bleaching powder:

In Bachmann's plant, bleaching powder is produced in the following ways:

The complete apparatus is set up to produce bleaching powder and includes a vertical cast-iron tower with a hopper at the top, two inlets near the base (one for chlorine and the other for hot air), and an exit for waste gases towards the top. Then, this tower is equipped with shelves that are positioned with spinning rakes at various heights. There are eight shelves altogether. The hopper is filled with slaked lime. It finally makes touch with chlorine, which is steadily flowing upward. Then, at the tower's base, in the barrel region, the bleaching powder is gathered. In short, Chlorine gas, which is a byproduct of the Chlor-alkali process, reacts with dry slaked lime (Ca(OCl2)) to create bleaching powder.

Conditions to be looked after during the manufacture: 

  • The chlorine used should be dilute in nature. 
  • The temperature should be maintained below 40°C.

Bleaching powder's characteristics:

  1. The scent of chlorine is very noticeable in bleaching powder, which is a light yellowish powder.
  2. Chlorine is created by a reaction with weak acids.
  3. It can be dissolved in cold water. After dilution, the lime is left as an insoluble residue.
  4. The chlorine from the bleaching powder is released when it reacts with an excess of a diluted substance, like diluted sulfuric acid. As a result, the chlorine created when diluted acid reacts with bleaching powder serves as a bleaching agent. Thus, the bleaching agent in bleaching powder is chlorine.

Bleaching Powder Applications

  • It is employed in the textile sector as a bleaching agent for cotton and linen as well as for the laundry's use in bleaching soiled clothing. Bleaching powder is mainly used for removing colors from materials.
  • Due to its potent oxidizing properties, it is employed as an oxidizer in numerous industries.
  • It is employed as a disinfectant to purify water so that it can be consumed.
  • Used in the papermaking business to bleach wood pulp.
A few of bleaching powder's negative consequences include:
  1. Because bleaching powder fumes are so potent, breathing them in can have a variety of negative health effects.
  2. The skin is severely corroded and irritated by it.
  3. It might also cause lumps to develop in the eyes.
  4. Human tissue could be burned both internally and externally.

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