Pesticides and disasters

This last couple of weeks I have been thinking about pesticides, cyanide, toxic gases and other poisons.  Most of what is taught is abstract and fact filled.  We know how cyanide and organophosphate pesticides work.  We also know how to treat patients that get exposed.  Many times that treatment is lifesaving.  But sometimes the exposure is so great, the scope so immense that all we can do is turn away in horror and pray for victims.

In 1969 Union Carbide built a chemical plant in Bhopal, India to make the pesticide carbaryl (a carbamate insecticide).  The process used in Bhopal utilized methyl isocyanate as an intermediate.  Phosgene, an extremely toxic gas, was also used as an intermediate.  Right from the start safety was a concern at the plant.  Warnings were issued by multiple groups over a number of years over differing parts of the manufacturing process.  There were multiple small leaks, some resulting in death. 

Then on the 2nd and 3rd of December, 1984 the unthinkable happened.   Water entered a tank that was over filled with methyl isocyanate.  A runaway reaction ensued.  The exothermic reaction increased the temperature within the holding tank resulting in the automatic opening of a release valve.  A toxic gas cloud resulted.  The cloud was blown over the city of Bhopal.  The principle component of the cloud was methyl isocyanate.  In addition the cloud may have contained hydrogen cyanide, phosgene, carbon dioxide and other gases.  The gas was heavier than air staying close to the ground. 

It has been estimated that over 500,000 people were exposed to the toxic cloud.  Many animals died, even the leaves on the trees yellowed and feel off.  The immediate death toll was 2.259 people.  But total estimates range upward to 20,000 deaths and over 500,000 injuries.  The long term effects on health are still being felt today.  The total scope of this man-made disaster may not be known for decades. 

Today, on the anniversary of this horrific event, think about cost of pesticides we demand.  In Bhopal India that cost is not measured in bushels of produce or dollars per acre.  It is measures in the deaths of loved ones and the lingering health effects in others.