Memory foam products release, or off gas, organic compounds when they decompress. This smell lasts one to four days and is safe. The flexible polyurethane foam we use to make mattresses and mattress toppers is CertiPUR-US® certified, which means the foam has been independently tested for content of materials used, physical performance, and environmental stewardship. The flexible polyurethane foam is made without prohibited phthalates, ozone depleters, CFCs, formaldehyde, mercury, lead, or heavy metals and is low emission (VOCs) for indoor air quality.