CARMEL, Ind. (AP) — Eight members of Carmel High School’s wrestling team have forfeited matches after the suburban Indianapolis school reported that they wore banned weight-loss suits during practices.

The Indianapolis Star reports that the school informed the Indiana High School Athletic Association that several students had used the suits, which are commonly known as “sauna suits.”

The rubber, vinyl, and plastic-type suits are banned by the NCAA and National Federation of State High School Associations because they can cause severe overheating and dehydration, sometimes causing death.

Carmel’s athletic director sent a letter to athletic directors of other schools in the Metropolitan Interscholastic Conference addressing the violations.

WRTV-TV obtained that letter, which says eight student-athletes at the school “forfeited matches throughout the course of 19 different competitions during the season.”