District stores are not selling any children's sleepwear treated with Tris, the flame-retarded chemical believed to cause cancer, an official of the D.C. Office of Consumer Protection said this week.

Investigators for the office completed a survey of 34 stores in the District that stock children's night clothes after scientists issued new warnings last week. James Toughill, consumer education information officer, said that the 34 firms are believed to be the only ones in D.C. selling children's night clothes.

The survey was done by consumer investigators posing as shoppers, Toughill said. They checked for garments made of acetate, acetate blends, triacetate and triacetate blends, the fabrics that are nearly always treated with Tris, he said.

Nightwear made from 100 per cent polyester may in some cases be treated with a flame of 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 warned last week that 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 as an impurity trace amounts of a pesticide, DBCP, 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 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 these chemicals through direct absorption from 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 bump it," he said.

Federal law requires that children's night clothes sized 0 through 14 be flame-resistant, but it does not require that any chemicals used to make fabric meet this standard be specified on labels. Thus, the only way that parents can avoid buying clothing treated with fire-retardants suspected of being carcinogens is to check labels for the fabrics the sleepwear is made from.

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 Leavil.

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 retardents, according to Pittle. Nylon sleep clothes generally are treated by the addition of a chemical other than Tris, he said.

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

Parents who questions or comments may call the Consumer Product Safety Commission's hotline, 800-638-2666 in all states except Maryland and 800-492-2937 in Maryland. The hotline has been getting about 100 calls a week about Tris-treated nightwear, said a commission spokesman.

Tris-CP, in which chlorine replaces the bromine in tris-BP, "has not gone through the kind of scrutiny," that tris-BP has been subjected to, and it is not banned.

"I certainly don't want this to stay unresolved," said Pittle. He added that representatives of the Berkeley laboratory that has warned against tris-CP and of Stauffer Chemical Corp., which manufactured Fyrol FR 2, the agent in tris-CP, have been asked to meet with commission officials Friday to discuss tests run on the chemical.

A spokesman for Stauffer said tests made on Fyrol FR 2 for the company had results opposite of those found by biochemists Ames and Blum in California. The Stauffer tests, made by Litton Bionetics of Kensington, Md., did not show that Tris-CP is a mutagen and possibly cancer-causing, he said.

The Stauffer spokesman said the company stopped selling Fyrol FR 2 in May this year after the firm received reports that there was "uncertainty" about the safety of the chemical.

The Environmental Defense Fund estimates that from 1.8 million to 2.5 million sleep garments treated with the Fyrol FR 2 chemical may still be on the market, Rauch said. He said that many of the winiter nightgowns and pajamas going on sale now, particularly those made of 100 per cent polyester, may be treated with the chemical.

The Stauffer official placed the estimate lower, at around 1 million garments.