[Hunker.com] "Polyurethane foam has been one of the materials for crib mattress pads for many year but questions remain about its safety. Evidence shows that it isn't the best material for a baby to sleep on, with health hazards eminently present. Polyurethane foam is no longer deemed safe for babies, as shown by a study published in Environmental Science & Technology.
The manufacturing of polyurethane foam starts with a petroleum base. Various chemical processes create the final product and the chemicals are still in the final product, which a baby continuously breaths when sleeping on a polyurethane foam mattress pad.
According to Healthy Child, typical chemical additives may include formaldehyde, benzene, and toluene. Additional chemicals this material are classified by the EPA as hazardous air pollutants."