Pesticides and Other Organic Molecules

Pesticides and Other Organic Molecules

Bhopal Chemical Accident:

Accident occurred in the early morning hours at the American-owned Union Carbide pesticide plant which manufactured Sevin.

On December 3 1984, more than 40 tons of methyl isocyanate gas leaked from a pesticide plant in Bhopal, India, immediately killing at least 3,800 people and causing significant morbidity and premature death for many thousands more.

• Plant was in an area zoned doe light industrial and commercial use not for hazardous industry during the 70s. Was initially approved for manufacturing the pesticide from component chemicals like MIC imported from it's parent company and only in relatively small quantities
• Pressure from competitors prompted the UCIL to produce the raw materials and intermediate products within one facility.

These same chemicals are implicated as human health hazards

Considered the worst

industrial accident in history

According to WHO..

"Chemicals may have immediate, acute effects, as well as chronic effects, often resulting from long-term exposures. About 47 000 persons die every year as a result of such poisoning. Many of these poisonings occur in children and adolescents, are unintentional (“accidental”), and can be prevented if chemicals were appropriately stored and handled. Chronic, low-level exposure to various chemicals may result in a number of adverse outcomes, including damage to the nervous and immune systems, impairment of reproductive function and development, cancer, and organ-specific damage.

By 1984 the plant was suffering economically and was only operation and 1/4 of it's production capacity. The plant was to be dismantled but it continued to operate at low safety levels. The government was aware but did not attempt to regulate :

" The Bhopal disaster could have changed the nature of the chemical industry and caused a reexamination of the necessity to produce such potentially harmful products in the first place. However the lessons of acute and chronic effects of exposure to pesticides and their precursors in Bhopal has not changed agricultural practice patterns. An estimated 3 million people per year suffer the consequences of pesticide poisoning with most exposure occurring in the agricultural developing world. It is reported to be the cause of at least 22,000 deaths in India each year. In the state of Kerala, significant mortality and morbidity have been reported following exposure to Endosulfan, a toxic pesticide whose use continued for 15 years after the events of Bhopal"

• on December 2nd around 11pm a plant operator noticed a small leak of MIC gas in increasing pressure inside a storage tank
• The vent-gas scrubber, a safety device designer to neutralize toxic discharge from the MIC system, had been turned off three weeks prior. A faulty valve had allowed one ton of water for cleaning internal pipes to mix with forty tons of MIC and a 30 ton refrigeration unit that normally served as a safety component to cool the MIC storage tank had been drained of its coolant for use in another part of the plant
• This caused pressure and heat from the vigorous exothermic reaction in the tank to build.

The explosion

Hazardous Chemicals

• Around 1am a safety valve gave way in the plant, causing and explosion and sending a plume of MIC gas into the air.
• 3,800 people died immediately, mostly in the poor slum colony adjacent to the plant.
• it's estimated that 10,000 people died in the immediate aftermath of the accident with and additional 15,000 to 20,000 premature deaths occurring in the following 2 decades.

A hazardous chemical, as defined by the Hazard Communication Standard (HCS), is any chemical which can cause a physical or a health hazard.

Hazardous Chemicals are essential to the function of modern society...

• Fun fact: Over 15,000 made and used in the united states.

Why it's dangerous..

CARBAMATE

Methyl Isocynate (MIC)

• Close relative of organophosphates pesticides
• Dissipate quickly from the environment
• Some are approved for control of garden pests.

an intermediate chemical used in the manufacturing of Carbamate pesticides

Examples:

How do we get exposed?

Colorless highly flammable liquid with a strong odor.

Used in the pesticides, polyurethane foam, and plastics

• Can be found in smoke from tobacco
• Breathing it our touching it at workplaces where it's produced or used
• living in a near facilities that manufacture, use, or store the chemical. (low levels from inhalation.

Agency for Toxic Substances and Disease Registry Profile:

• Carbyl (Sevin)
• Aldicarb
• Fenoxycarb
• Propoxur
• Metam sodium

What happens when it's released into the environment:

Health effects:

• In air: exists solely as a gas. Broken down by substances found in the air and by moisture or rainfall. Will only persist in the atmosphere for a few hours to a few days before being degraded.
• In water: rapidly degraded into other substances. Ex: Urea. Will only persist in water for minutes to a few hours.
• In soil: will be broken down into compounds when it reacts with the moisture in soil or will evaporate into the air
• Does not accumulate in the food chain.

• Most harmful when inhaled.
• effects will depend on how much exposure you received and how long.
• low level exposure can cause eye and throat irritation
• high level exposure can cause the lungs to swell resulting in difficulty breathing. Can happen quickly or after 1 to 2 days. Severe lung dammage that may be irreversible is possible and it can be fatal.
• Not considered carcinogenic

OSHA has set an exposure limit of 0.02 ppm for workplace air for an 8 hour workday and 40 hour week.