INDIANAPOLIS (AP) — A U.S. Senate committee wants the NCAA to start providing college athletes with greater protections from “exploitative practices” on campuses.

In a letter addressed to NCAA President Mark Emmert and obtained by The Associated Press on Monday, the Committee on Commerce, Science and Transportation asked the NCAA to send information describing what protections are already in place. The letter, signed by three Democrats, insisted more needs to be done for athletes.

The senators wrote that if the NCAA was accomplishing its mission by protecting college athletes, there would be no need for a players’ union. In February, a National Labor Relations Board regional office ruled that Northwestern’s football players could unionize. A vote was held in April, but the decision has been appealed.