Sixteen thousand residents of Pittsburgh had to be evacuated from their homes April 11 when 200 gallons of phosphorus oxychloride spilled during a Conrail freight train derailment. The tank car that leaked the 200 gallons held 36,000 gallons of the highly corrosive Class B poison. The chemical belonged to Monsanto Corp. of St. Louis, MO and was en route to Monsanto's plant in Bridgeport, NJ; the spill occurred through the safety valve on the derailed car. Emergency response personnel plugged the leaking valve with a tennis ball. The threat that the phosphorus oxychloride might react with water to produce a cloud of hydrochloric acid led to the evacuation. Local residents were evacuated a second time within 24 hours while cranes righted the derailed car and the dangerous chemical was pumped into waiting tank trucks.
--Peter Montague, Ph.D.

Descriptor terms: spills; evacuations; monsanto; conrail; poisons; pa; pittsburgh; phosphorus oxychloride; monsanto; trains; transportation accidents;