Legislation that would ban the sale of “bath salts” and “Spice,” which was approved by the U.S. House in December, has stalled in the Senate, American Medical News reports.

The Synthetic Drug Control Act, approved by the House on December 8, bans more than 30 synthetic drugs, including bath salts and Spice. The measure would make it illegal to manufacture or dispense the drugs.

The bill would also give the Drug Enforcement Administration more authority to put temporary bans on potentially hazardous drugs as they are being investigated. The measure passed by a vote of 317 to 98. If it is passed by the Senate, bath salts and Spice will be put on a list of controlled substances. Researchers wishing to study them would need a license to obtain samples.

The legislation is supported by groups representing physicians and public health officials. The Senate version of the bill, introduced by Senator Charles Grassley of Iowa, is being delayed by an objection from Senator Rand Paul, MD, of Kentucky, according to Senator Grassley’s office. Dr. Paul did not respond to inquiries by the publication seeking comment.

The American Association of Poison Control Centers reported 6,072 calls in 2011 about human exposures to bath salts, compared with 303 the previous year.