YORK, England, Sept. 20 (UPI) -- A team of British, Canadian and U.S. scientists discovered a significant presence of phosgene, once used as a chemical weapon, in the Earth's atmosphere.

Although used as a chemical weapon during World War I, its continued presence in the atmosphere is said to be due to man-made chlorinated hydrocarbons used in the production of pharmaceuticals, herbicides, insecticides, synthetic foams, resins, polymers and other chemicals.

From February 2004 to May 2006 researchers used the Canada Space Agency's Atmospheric Chemistry Experiment satellite to conduct the first study of the global distribution of the gas.

The scientists discovered the main atmospheric concentration of the gas was above the Equator, though it was present in some quantity in all latitudes.

"It's very toxic and pretty nasty stuff -- its reputation is well deserved," said Professor Peter Bernath of the University of York. "Considering the health hazards associated with phosgene, the chemical industry is trying to find substitutes to eliminate its use."

Higher in the atmosphere, phosgene can be slowly oxidized by ultraviolet rays and so it continues to play a role in the depletion of the ozone layer.

The research is published in the latest edition of Geophysical Research Letters.