Schumer's bill, Combating Dangerous Synthetic Stimulants Act of 2011 (S.409), enjoys bipartisan support, and would place a federal ban on mephedrone and methylenedioxypyrovalerone (MDPV), which are commonly sold under the deceptive label of “bath salts.” 

Paul apparently also has placed a hold on two companion bills that would also ban synthetic marijuana known as "spice," and other designer drugs.

"One of my colleagues has a hold on these bills — Senator Rand PaulRandal (Rand) Howard PaulConservative pundit says YouTube blocked interview with Rand Paul These Senate seats are up for election in 2022 I'm furious about Democrats taking the blame — it's time to fight back MORE, the junior senator from Kentucky," Schumer complained. "One senator shouldn’t be able to prevent a vote on something that 99 percent of Americans want that directly affects their health and safety and the health and safety of their children.

"I hope that Senator Paul will agree, not to set aside his differences, which I respect, but to let these bills come up for a vote," concluded Schumer. 

Paul's spokesman told The Hill on Tuesday that he will respond to Schumer later on Wednesday.