Children’s sleepwear has been the subject of controversy since the 1970s. The original rules for baby pajamas were adopted by the Department of Commerce in 1971 and the enforcement was subsequently transferred to the Consumer Products Safety Commission (CPSC). The guidelines specified that garments, including trim and seams, must self extinguish when exposed to an open flame for 3 seconds. The product must pass the test new and again after going through fifty wash cycles. Polyester was a common fabric for baby pajamas at this time and met the requirements for flame resistance due to its inherent qualities. Other fabrics needed to be treated, and one of the first chemicals developed for this function was tris (2, 3-dibromopropyl) phosphate, commonly referred to as TDBPP, tris-BP or just TRIS. This process was short lived as research uncovered the fact that it caused cancer and sterility in animals. TRIS was officially banned in 1977 and consumers were left with a bad impression of chemical treatment and limited options for sleepwear.  The public continued to show interest in the softer and more comfortable option of 100 % cotton pajamas, so merchants marketed cotton jumpers and other clothing as “daywear” or “playwear”. The CPSC wanted to avoid confusion, so they amended the sleepwear regulations in 1996. Cotton garments were approved for use as sleepwear if they fit the specification for snug fitting, the rationale being that eliminating airspace, and thus oxygen, between the garment and the child’s skin significantly reduces flammability. It was also noted that cotton pajamas were acceptable for babies under nine months due to their limited mobility. In recent years, polyester and untreated cotton have been the predominant types of children’s pajamas available to the public. It has been estimated that less than 1% of this sleepwear is actually treated with any type of chemical, yet there is still controversy surrounding this subject. There are two main reasons for the current focus on this topic. First, a number of major lines of children’s clothing have recently started selling 100% cotton pajamas treated with flame retardant, which will be addressed below in the discussion of available options. The other reason, which has attracted much more public interest, is the concern about brominated flame retardants. There is a growing body of evidence showing brominated flame retardants are contaminating the environment and accumulating in the human body. The most widely studied and publicized of these chemicals are the polybrominated diphenyl ethers (PBDEs), which have proven to impair thyroid functioning and damage the nervous and reproductive systems. They have already been banned in Europe and the United States is considering similar legislation. While this issue is cause for concern, these chemicals are not used in baby’s pajamas, as some sources have mistakenly claimed. They are most commonly found in computers, televisions, mobile phones, automotive and construction materials, mattresses, carpets and upholstered furniture. Other types of brominated flame retardants have been used in children’s pajamas, but it is extremely uncommon. The most important thing that parents can do is become informed about what they are purchasing. If you do choose to buy treated pajamas, contact the company to find out what they are using. In general, garments are referred to as flame resistant if the fabric meets the CPSC guidelines without needing treatment, while the term flame retardant is normally used if a chemical has been added. Following is an overview of the three most commonly available types of sleepwear.Polyester: Polyester is considered to be “inherently” flame resistant. Flame retardants are actually chemically inserted during the manufacturing process and become part of the molecular composition of the fabric. The resulting polymer is very stable, so there is little likelihood that any chemicals could be released from the garment. The main complaint about polyester pajamas is that the fabric does not breathe and can thus contribute to overheating and rashes. You may also want to consider the fact that polyester has a negative impact on the environment, releasing nitrogen and sulphur dioxides, hydrocarbons, carbon monoxide and heavy metals. Cotton treated with flame retardants: Many major lines of children’s clothing have recently started marketing 100% cotton flame retardant pajamas. Most of the companies are using a treatment called PROBAN, which is made from the chemical tetrakis hydromethyl phosphonium chlorida (THPC) and added to the fabric or garment in the finishing stages. During the process, the flame retardant molecules penetrate the cotton fibers. The fabric is then dried and cured, which causes a water insoluble polymer to form, essentially trapped inside the core of each fiber. The end result maintains all the desirable qualities of cotton, such as softness and moisture absorbency. If a flame comes into contact with PROBAN treated cotton, an insulating char forms and protects the fabric from further damage. Studies indicate that the treated fabric has low migration of any chemicals and does not cause any skin irritation, yet some consumers still have concerns. The THPC used in the process has been linked to genetic abnormalities as well as damage to the liver, skin and nervous system. It also promotes the growth of cancerous tumors. Due to the potentially dangerous nature of these chemicals, questions arise about the safety of the manufacturing process and there has been no monitoring of environmental exposure. Untreated Cotton: As mentioned above, cotton pajamas meet CPSC guidelines if they are snug fitting. These are the clear choice for many parents, eliminating any concerns regarding chemical treatment either during or after the manufacturing process. Some even recommend taking the next step and buying only organic cotton sleepwear, which is made using no pesticides. In the end, parents must decide if concerns about chemical use and the environment outweigh their concerns about fire safety. Many children’s activist groups are in opposition to the CPSC’s decision to include untreated cotton garments as acceptable sleepwear, while environmental groups oppose the use of chemical additives. Consumers should continue to educate themselves about the issues and keep abreast of current research so they can make informed choices.