Ed Postawko, chief warrant officer for the St. Louis circuit attorney’s office, said few cases have made it to court in recent years.

“In large part, we have to rely on what the lab says,” Postawko said. “If the chemist isn’t sure, how can we be? That’s the thing — you make something illegal, then (drugmakers) change the chemical compound into something that’s not illegal. Laws don’t get changed overnight.”

Chris Perry, 35, who is homeless, said he has seen some people have bad reactions but thinks the fears are overblown.

“I don’t think it’s that bad,” Perry said. “I zombied out once. You build up a tolerance to it. They’re making a big deal out of it because it’s the homeless, and they’re trying to clear us out. They want us out of downtown.” He said an overdose “is the last thing I’m worried about.”

Some people on probation for crimes choose synthetic drugs instead of marijuana, heroin or cocaine to avoid failing drug tests, said Bryan Goodlow, 28, who is homeless and on probation. He knows smoking K2 can be risky but said he does it anyway, despite seeing others overdose in recent weeks.

“I’m going to die one day, anyway,” Goodlow said. “I just like getting high. That K2 is a mind trip. It pulls demons. If you don’t know what you’re getting into, if you’re in some pain, then don’t do it because when you hit that, your brain runs 100 miles an hour.”

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