Toxins of Bhopal Gas Tragedy 1984

Context: Toxic waste weighing 337 tonnes from the defunct Union Carbide factory has been completely incinerated at a private waste treatment facility in Pithampur industrial area, Dhar district in Madhya Pradesh. The waste was moved to the treatment facility in early 2025, more than 40 years after the Bhopal gas tragedy. 

Relevance of the Topic:Prelims: Heavy Metals, Persistent Organic Pollutants. 

What was the Bhopal Gas Tragedy? 

• The Bhopal disaster or Bhopal gas tragedy was a chemical accident on the night of 2–3 December 1984 at the Union Carbide India Limited (UCIL) pesticide plant in Bhopal, Madhya Pradesh.
• The world's worst industrial disaster occurred due to the release of nearly 40 metric tons of methyl isocyanate (MIC) from the plant. Over 5000 people lost their lives and thousands suffered physical disabilities due to the leak of toxic methyl isocyanate gas. 

Read also: Industrial Disaster

Toxins associated with Bhopal Gas Tragedy: 

• Along with MIC, past reports have indicated the release of worrisome concentrations of toxins, persistent organic pollutants (POPs) and heavy metals.
  • Toxins included: Hexachlorobutadiene, Chloroform, Carbon tetrachloride, Trichlorobenzene
  • Heavy metals: Mercury, chromium, copper, nickel, and lead.

What are Persistent Organic Pollutants (POPs)?

• Persistent Organic Pollutants (POPs) are organic compounds that do not break down easily and remain intact in the environment for long periods.
• They become widely distributed geographically, accumulate in the fatty tissue of living organisms and are toxic to humans and wildlife.
• Their effects include- Cancer, allergies and hypersensitivity, damage to the central and peripheral nervous systems, reproductive disorders, and disruption of the immune system.
• The Stockholm Convention on POPs is an international environmental treaty to protect human health and the environment from POPs.
  • The Convention was adopted in 2001 and came into effect in 2004. 
  • India is a party to the Convention. 

What are Heavy Metals?

• Heavy metals are a group of metals and metalloids that have relatively high densities, atomic weights, or atomic numbers. They are classified as heavy metals because their density is at least 5x that of water. 
• They are often characterised by their toxicity, persistence in the environment, and potential to bioaccumulate in living organisms and have adverse effects on human health and the environment.

• Common Examples:
  • Mercury: Can damage multiple organs even at low concentrations by accumulating in soft tissue and preventing normal cellular function.
  • Lead: 
    • Can damage chlorophyll and disrupt photosynthesis in plants. 
    • Developmental issues, brain impairment & cancer. 
  • Arsenic: Carcinogenic. 
  • Chromium: Carcinogenic, impair immune system. 
  • Nickel: Carcinogenic.