The U.S. Senate, in a 96-1 vote, approved a Food and Drug Administration bill last week that includes an amendment supported by Sen. Susan Collins that would ban synthetic chemicals used to make the street drug bath salts.

The measure, which also would outlaw synthetic marijuana, now needs to be reconciled with a similar bill that passed the House.

“The amendment, introduced by Senator [Rob] Portman, was unanimously approved by voice vote Thursday,” Collins spokesman Kevin Kelley said Tuesday.

Portman is a Republican from Ohio.

The FDA measure combines three bills previously introduced by Sens. Chuck Grassley, R-Iowa, Chuck Schumer, D-N.Y., and Amy Klobuchar, D-Minn. It outlaws dozens of synthetic drugs, including mephedrone and methylenedioxypyrovalerone, known as MDPV, which can be used to make bath salts. The bill carries a penalty of up to 30 years for those caught selling the deadly synthetic drug.

The lone dissenter in last week’s vote was Sen. Bernie Sanders, an independent from Vermont.

Bath salts emerged on the streets of Bangor in February 2011 and by July — when the drug was banned in Maine — it had grown into a problem that had spread throughout the state.

The drug, which can be snorted, smoked, injected or swallowed, is addictive and causes users to act unpredictably, officials have said. It has caused hallucinations, convulsions, psychotic episodes and thoughts of suicide in users, and has been linked to more than one death in Maine.

Police say a naked man who attacked and was caught eating the face of another naked man on a Miami, Fla., highway on Saturday was high on the drug, according to a CBS News report.

Collins and fellow Republican Sen. Olympia Snowe both are co-sponsors of the Combating Dangerous Synthetic Stimulants Act, the bill proposed by Schumer.

“I am pleased the Senate passed a provision while considering the Food and Drug Administration Bill to take a crucial step in stopping the spread of bath salts,” Snowe said in a statement Tuesday. “The severity of the bath salts crisis cannot be overstated. This use of these mind-altering drugs are resulting in prolonged, violent episodes and greatly stressing the resources of local law-enforcement and medical facilities.

“Let me be clear, the toll it has taken on our state and the health of our citizens is significant, and disturbing reports of violent and self-destructive behavior are deeply concerning and must be addressed at all levels of government,” said the longtime senator for Maine, who is retiring at the end of her current term.

The U.S. House of Representatives in December passed the Synthetic Drug Control Act of 2011, which carries a penalty of up to 20 years in prison for those caught dealing in the listed hallucinogenic synthetic drugs.

The U.S. Drug Enforcement Administration took emergency action in September 2011 to federally ban mephedrone, Methylone and MDPV and designated the hallucinogenic stimulants a Schedule 1 drug, the same class as heroin and LSD.

Bath salts already are banned in much of Europe, where they surfaced in the mid-2000s as a club drug.

Collins has said that the bath salts crisis is a “national threat that requires national action.” She has co-sponsored legislation that would require better coordination between federal and local law enforcement agencies targeting the spread of synthetic drugs such as bath salts.

A final version of the combined House and Senate bills is expected to be presented to President Barack Obama in early July.