"This is pretty good [stuff]," says one young teenage boy, inhaling deeply from a bong made out of a plastic water bottle.
Some commenters on the videos warn their fellow users of serious side effects. "I know people that had strokes. It makes your heart beat real fast," wrote one.
"That stuff gives me panic attacks," wrote another.
Dr. Joshua Sharfstein, Maryland's health secretary, says the availability of synthetic marijuana can lead people to think it is safe.
"Just because something is sold at a gas station does not mean it is safe for kids," Sharfstein said. "Synthetics have been linked to some very serious side effects: catatonia, seizures, hallucinations."
Sharfstein lobbied the state legislature this year to impose a state ban on synthetic marijuana, without success. He lauded the federal ban, which covers not just chemicals known to mimic marijuana, but also their chemical analogs. In the past, manufacturers of such products have responded to more narrowly worded bans by slightly altering chemical formulas.
"It's really easy to evade lists of chemicals because you can just tweak the molecule," Sharfstein said.
Data from Maryland's Poison Control Center show that 159 people contacted the center after using synthetic marijuana from the beginning of the year through mid-August, a slightly higher rate than last year. Four people wound up in critical care units and five in psychiatric facilities after using such products. Eleven others were hospitalized in regular hospital units.
Dr. Bruce Anderson, director of the Poison Control Center at the University of Maryland's School of Pharmacy, noted that the data does not show the number of people who used a drug, only those who contacted the center after being concerned about its effects.
In contrast, 50 people contacted Poison Control about marijuana use during the same period and 50 called about bath salts use.
Kotowski warned that even as authorities try to stamp out synthetic marijuana, manufacturers are likely cooking up new drugs to skirt existing laws — and people will be willing to try them.
"If people were told they could get high taking rat poison, they would take it," he said.