But now that "Spice" and other forms of imitation pot are sending users to emergency rooms across America, the retired professor has an idea of how to stem the epidemic. If the federal government would legalize the real thing, says Huffman, maybe consumers wouldn't turn to the far more dangerous fake stuff.
Huffman, who developed more than 400 "cannabinoids" as an organic chemist at Clemson University, says that marijuana has the benefit of being a known quantity, and not a very harmful one. We know the biological effects of THC, the active ingredient in marijuana, Huffman told ABC News, because they have been thoroughly studied. "The scientific evidence is that it's not a particularly dangerous drug," said Huffman.
The "JWH" class of compounds that Huffman invented to mimic marijuana's effects, meanwhile, have not been tested the same way. "The physiological compounds effects of [JWH] compounds have never been examined in humans," said Huffman. What we do know, he says, is that "it doesn't hit the brain in the same way as marijuana, and that's why it's dangerous."
While they are known to elevate blood pressure -- unlike marijuana -- and to cause increased heart rate and anxiety, to date most of the evidence of their effects is anecdotal, and comes from things like visits to emergency rooms. "There have been a number of people who've committed suicide after using them," said Huffman.
Huffman began working on the cannabinoids in the early 1990s using a grant from the National Institute for Drug Abuse. He published academic papers that gave information on the chemical steps to make the compounds, including JWH-018, one of the easiest of the class to make and the one most often found in Spice products.
"JWH-018 can be made by a halfway decent undergraduate chemistry major," said Huffman, "in three steps using commercially available materials."
In 2008, says Huffman, someone sent him an article from the German magazine Der Spiegel about a young man using the JWH chemicals to get high. He subsequently learned that the "imitation marijuana" drugs based on his chemicals had popped up in Europe in 2006, not long after he'd published a paper describing how to make the compounds. The compounds were also being used commercially in South Korea as a plant growth product, and Huffman speculates that they migrated from there to China, where they are now being manufactured for use in Spice.
"I figured that somewhere along the line, some enterprising individual would try to smoke it," said Huffman. He didn't figure that it would become a global industry.
Anyone who ingests it recreationally, Huffman stressed, is "foolish" and playing "Russian Roulette," and the head shop owners who are selling it know what they are doing. "They can read the newspapers, they can watch TV," said Huffman. "They know what's in it. And I think they're exploiting the young people who buy them." A representative of a head shop trade group told ABC News that the products should be regulated but not outlawed.