Harlow's Earth Crib Mattress Covers create a safer sleeping environment that protects your little one from potential chemical off-gassing and allergens found in many crib mattresses. Wrapping your baby's crib mattress is a simple intervention to give you peace of mind. What makes a mattress toxic? PVC is a known human carcinogen linked to cancer, birth defects, learning and developmental delays, endometriosis and immune abnormalities. Flame Retardants can cause cancer, reduced IQ, developmental delays and reproductive difficulties. Polyurethane Foam affects the nervous and immune system, causes neurological disorders, autoimmune weakness, asthma, allergies, infertility, miscarriage and child behavior disorders. Our product was developed in response to SIDS research in New Zealand stating that poisonous gases are being generated in the mattress where the baby sleeps. The toxic gas theory, presented by Dr. James Sprott, states that the chemicals: phosphorus, arsenic and antimony are very frequently present in bedding. When these chemicals mix with naturally occurring molds found in the baby's mattress, the gases shut down the central nervous system, resulting in the cessation of breathing and heart functions- SIDS. Our specially-formulated crib mattress covers are impermeable to these toxic gases as well as: BPA, Latex, Phthalate and Lead free. They are made of 100% virgin polyethylene and are 6mil in thickness. Our mattress covers are also waterproof and recyclable.