Illinois Sen. Mark Kirk publicly called for the Chinese government to do more to stop the drug from entering the U.S. Monday.
The request comes in the aftermath of an NBC 5 investigation which demonstrated the near-constant flow of synthetic marijuana through the postal facility at O'Hare International Airport.
"These synthetic drugs are a significant threat to public health and safety," Kirk said, in a letter to the Chinese ambassador Cui Tiankai. "The majority of these substances are produced and packaged in China, and exported to the United States. I ask your government to take immediate measures to crack down on this growing industry."
Officials with Customs and Border Protection say they make daily seizures of the drug, which arrives almost exclusively from China in the form of a white powder. Once in the United States, it is mixed with acetone, sprayed on some kind of smoking material, (often common potpourri), and sold in packets under brand names like "Spice" and "K2."
"It's a growing problem said Bill Ferrara, CBP's Director of Field Operations. "With the help of scientists we have here, we can identify these drugs much more quickly than we have in the past."
Synthetic pot initially became popular in the United States as purchasers believed they were buying legal and safe versions of marijuana, with brightly colored and seemingly legitimate packages sold in convenience stores and truck stops. Touted as "herbal" products, the drugs were actually created in laboratories.
U.S. authorities say every time one is declared illegal in the United States, chemists in China reformulate the recipes, creating new, and theoretically "legal" versions.
Illinois is one of several states which passed sweeping legislation four years ago, designed to ban even future derivatives.
"I would note that you have no idea what dangerous poison is in this stuff," Kirk said Monday, following a tour of the Customs and Border Protection post inside the U.S. Postal Service facility at O'Hare. "We want to make sure as many citizens don't die from this stuff as possible."