Once upon a time, most children's sleepwear was loose-fitting. This type of sleepwear had a higher risk of catching fire near open flames, like cigarettes or candles. In 1953, the Federal Trade Commission (FTC) passed the Flammable Fabrics Act.

In 1967, lawmakers moved this act to the Consumer Product Safety Commission (CPSC). In 1975, the sleepwear portion of the act was enacted which required children's sleepwear - ages 9 months to 14 years - meet a standard to create flame resistant products.

This requirement was for childen's sleepwear only. The idea was that children were in their pajamas during morning and evening hours when they were likely closer to open flames on stoves.

Cotton and cotton-blend garments do not meet this standard unless they are treated with a chemical that makes them flame retardant. By doing so, the product slows down ignition or combustion if it catches fire.

Studies found that some flame retardant chemicals in products are toxic. These include brominated and chlorinated tris, which the Environmental Protection Agency (EPA) banned. PBDEs may also cause learning disabilities and lower fertility. Similarly, researchers found these chemicals in carpets, furniture, and toys, some of which remain in homes and products.

Further studies showed that brominated tris could damage DNA and probably entered the body through the skin. And parents were sending their kids to bed in pajamas treated with the stuff!

In 1996, the CPSC amended the requirement that tight-fitting pajamas do not need to be flame retardant. This is because the tighter-fitting product has no air between the child's skin and the fabric. This means the fire gets less oxygen to spread.

This rule does not apply to children who are 9 months old or younger. These little ones are not mobile enough to get close to an open flame.