Lawmakers are demanding the government reinstate tougher fire safety standards for children's sleepwear, saying a relaxation of the rules threatens the health of many youngsters.

By accepting changes, the Consumer Product Safety Commission is "truly playing with fire," said Rep. Rosa DeLauro, D-Conn.But a commission spokesman said the problem is complicated by consumer resistance to flame-resistant nightwear and the fact that many parents send their children to bed in baggy T-shirts and other flammable garments.

Joined by fire chiefs, physicians, burn experts and fire victims, lawmakers called on the commission to reconsider its 1996 decision permitting the use of flammable material, such as cotton, in some children's sleepwear as long as the garments are tight-fitting and, thus, difficult to ignite.

At a Capitol Hill news conference Wednesday, DeLauro and Rep. Rob Andrews, D-N.J., said they do not intend to press for legislation to correct what they called a serious chipping away of a federal safety standard that has protected children for more than a quarter century.

They said they hoped public pressure would persuade the commission to return voluntarily to standards first established in 1972 requiring all children's pajamas, nightgowns and other sleepwear to be made of flame-resistant materials.

Under the old rules, children's sleepwear sizes 14 and under must be chemically treated to resist fire. Polyester garments are exempt because they don't catch fire as easily as other materials, such as untreated cotton.

The commission's 1996 rule change was based on staff findings of next to no injuries linked to tight-fitting sleepwear - such as a one-piece, footed pajama - or to night clothing worn by infants younger than 1 year old.

The safety commission said it is willing to reconsider its sleepwear decision, but only if advocates can produce data showing a change is required.