According to a study done by the Environmental Working Group, cleaning supplies used in 13 large California school districts release an airborne brew of chemicals, including a number that have been linked to asthma or cancer by state and federal health authorities. Tests of 21 cleaners from these schools conducted for the Environmental Working Group found that when used as directed, the products released six chemicals known to cause asthma, 11 contaminants that are known, probable, or possible cancer-causing substances in humans, and hundreds of other compounds for which thereis little or no hazard information.

In all, air testing revealed 457 chemicals emitted by these products. While some of these airborne compounds are known to be hazardous, nothing is known about the health risks of most of them. Manufacturers’ documents disclosed the presence of another 42 chemical ingredients that air testing could not pick up.Statewide, cleaning supplies release 32 tons of contaminants into the air each day.

Some of the products tested are widely used in American households, including Comet Disinfectant Powder Cleanser, which emitted 146 contaminants when used as directed, including formaldehyde, benzene, chloroform and four other chemicals identified by the state of California as causing cancer or reproductive harm.