U.S. Senator Bob Casey of Pennsylvania called on the Senate Judiciary Committee to close loopholes in a synthetic drug law that allows makers of the drugs to slightly alter their ingredients to avoid federal and state bans.

The Times Leader reports Senator Casey sent a letter to Committee Chair Patrick Leahy of Vermont, asking the committee to work with him on a bill to close the loopholes. He referenced a new synthetic drug called “Cloud Nine,” which is a variant of insect repellant that has the same effect as “bath salts,” the article states.

Casey said law enforcement officials are concerned this new drug will lead to an outbreak of violent and dangerous drug use. He wrote, “…despite recent progress on this issue by many states and an emergency ban by the Drug Enforcement Administration (DEA), it has become apparent that the makers of synthetic drugs will stop at nothing, and are already designing new chemical variations of these drugs to circumvent both state and federal bans once more.”

Legislation that would ban the sale of synthetic drugs, which was approved by the U.S. House in December, has stalled in the Senate. The Synthetic Drug Control Act, approved by the House on December 8, bans more than 30 synthetic drugs. 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.