A lawsuit filed in St. Louis charges three companies might have sprayed harmful chemicals in and over St.Louis in the 1950s.

The suit has been filed by a former city marshall who remembers as a boy seeing men in protective suits spraying what he thought was bug spray at his housuing complex.

The dissrtation raised concerns about a secret government spraying program described at the time as a test of a smoke screen system to protect the city from Soviet attacks.