The use of ozone-depleting substances in industry increased significantly until about 1990. The result has been serious depletion of the ozone layer. New data have recently revealed that the hole in the Antarctic ozone layer which appears each spring is now larger than was originally calculated, and there is evidence of a similar hole beginning to form over the Arctic. The serious implications this has for life on earth and human health have resulted in global action to protect the stratospheric ozone layer.