Parents concerned about new warnings from scientists on the dangers of flame retardant chemicals in children's sleepwear can choose night clothes made from one of several synthetic fabrics if they want to avoid chemicals together, according to the Consumer Product Safety Commission.

Officials in consumer affairs offices in Fairfax and Arlington Counties said they do not have the staff available to survey stores to find out whether they are selling night clothes treated with Tris, the flame retardant. The Fairfax Department of Consumer Affairs, however, plans to establish a consumer "clearing house" to provide information on "high controvery subjects" such as Tris-treated nightwear, an official said.

Staff members of the Alexandria Consumer Affairs Office were to decide this week whether to make a survey of stores selling children's sleepwear in the city, said a spokesman.

Fabrics that are inherently flame-resistant and do not require treatment with chemicals are those known as modacrylic, matrix and vinyon, the commission said. Blends of these fibres also are untreated. Brand names of night wear made from modacrylic fabrics are Verel, SEF, and Kanecaron; the matrix brand name is Cordelan, and the vinyon brand name is Cordelan.

Nightwear made from 100 per cent polyester may in some cases be treated with a flame retardant known as tris-CP that is now suspected of being a cancer-causing agent, according to an official with the Environmental Defense Fund. The EDF's position is that if a consumer "really wants to be safe you virtually have to avoid all 100 per cent polyester, and stick to the synthetic fibers" that are inherently flame-resistant, said the official, staff attorney Robert Rauch.

Two California scientists said last week that a flame retardant, Tris (tris-BP), banned by the government from use in children's night clothes because it might cause cancer, is closely related to, and contains trace amounts of a pesticide that "has been shown to cause sterility" in humans. The scientists, biochemists Arlene Blum and Bruce N. Ames of the University of California at Berkeley, said they fear that tris-BP could cause sterility, sperm mutations and testicular abnormalities in boys.

They also said their tests have shown that tris-CP, the fire retardant some children's sleepwear manufacturers began using after the ban on tris-BP, is a possible cause of cancer.

Blum and Ames said sleep clothes treated with tris-CP, which was not covered by last year's ban, and tris-BP "are being sold throughout the United States. Children are being exposed to large doses of the chemicals through direct absorption for fabric and from chewing on their sleepwear."

Legal challenges have partially frustrated the ban on tris-BP. Now when the commission finds retailers selling tris-BP nightwear "we're taking them to court" on an individual basis, said R. David Pittle, a member of the Consumer Product Safety Commission. The sleepwear "shouldn't be on the shelves. If it is, it's either ignorance or (the store) is trying to dump it," he said.

Children's sleepwear made from 100 per cent cotton is treated with a "chemical from an entirely different chemical family . . . that . . .is less suspect" than the Tris retardants, according to Pittle. Nylon sleep clothes generally are treated by the addition of a chemical other than Tris, he said.

Fibers that are treated with Tris are acetate, acetate blends, triacetate and triacetate blends, according to a commission announcement.

Parents with questions or comments may call the Consumer Product Safety Commission's hotline, 800-638-266 in all states except Maryland and 800-492-2937 in Maryland.