The cleansers, sprays, and stain removers you use to keep your home spotless are major sources of indoor toxins. A 2012 guide of more than 2,100 common cleaning products by the Environmental Working Group
(EWG), a nonprofit research organization, found that 53 percent contained chemicals like sodium or potassium hydroxide, which may damage the lungs (many oven cleaners have high levels), while 20 percent include carcinogens like formaldehyde. But don't rush out and buy everything you see with a "nontoxic" or "green" label. "Unfortunately, most cleaning products don't list all their ingredients, and even some with labels like 'all natural' still contain harmful substances," says Rebecca Sutton, PhD, an environmental chemist and contaminant specialist with the EWG. Look for cleaners with the EPA's Design for the Environment
label—a seal of approval given to products that contain only the safest levels of chemicals needed to get the job done.