Researchers analyzed 6 top-selling air fresheners & laundry products from plug-in oils to dryer sheets, fabric softeners, liquid spray air fresheners and detergents. The findings of the study, which was published online by the journal Environmental Impact Assessment Review, showed that all the products that had been submitted to the test were full of chemicals. Every single one contained at least one chemical considered toxic or hazardous to human health.

Anne Steinemann, civil and environmental engineering professor from the University of Washington, said in a statement that she was astonished to discover the quantity and potential toxicity the chemicals had. “Chemicals included acetone, the active ingredient in paint thinner and nail-polish remover; limonene, a molecule with a citrus scent; and acetaldehyde, chloromethane and dioxane.”

In the laboratory where the products were tested, each item was sited in an isolated space at room temperature. The surrounding air was examined too for chemical composition. The findings revealed that 58 different volatile organic substances had a concentration of at least 300 micrograms per cubic meter. For instance, a plug-in air freshener had no less than 20 different volatile organic compounds. Among these, seven are regulated as toxic or hazardous under federal laws.

Steinemann’s advised customers to pay attention to the products with fragrance they would like to purchase “because you really don't know what's in them.” She said she would like to see a better labeling system. “In the meantime, I'd recommend that instead of air fresheners people use ventilation, and with laundry products, choose fragrance-free versions."