At least 33 people in New York non-fatally overdosed on a synthetic drug known as K2 within 11 hours on Tuesday, according to the local news publication DNA Info. The drug, laced with chemicals meant to mimic the effects of marijuana, is on the rise in America, according to the Drug Enforcement Administration.

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Emergency medical responders in Brooklyn said they received dozens of calls about individuals behaving erratically and suffering respiratory problems on Tuesday.

One man told DNA Info that the scene resembled the television series "The Walking Dead."

"People were stumbling all over the place." "There was a couple of them trying to pick themselves up. One guy couldn't move at all. They had to pick him up by his pants to put him in the ambulance."

K2, one of several names for the synthetic drug class "spice," is sometimes referred to as "synthetic marijuana." ATTN: wrote about why that name is a misnomer, perpetuating a false equivalency to marijuana itself, which is not toxic and has no fatal overdose level. Spice is unregulated — often manufactured in Chinese labs and transported to the U.S., where it's sold in smoke shops and gas stations in some states.

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Because spice is unregulated, the drug's toxicity varies dramatically, and can sometimes contain high levels of synthetic cannabinoids.

Spice, or K2, is on the rise in America.

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The Centers for Disease Control and Prevention reports that calls to poison centers regarding spice overdoses have spiked since 2010. In the first four months of 2015, these calls increased 330 percent, Business Insider reports.

Both state and federal drug enforcement agencies are taking steps to curb the synthetic drug dilemma. In 43 states, there are bans on one or more synthetic cannabinoids, and the DEA has assigned multiple versions of the drug to a Schedule 1 category under the Controlled Substances Act. The problem is, by slightly altering the chemical structure of these drugs, new versions of the drugs are appearing on shelves legally in the U.S., despite the fact that they have similar effects.

According to the White House, the effects of consuming synthetic drugs such as spice include:

Severe agitation, anxiety, nausea, vomiting, tachycardia, elevated blood pressure, tremors, seizures, hallucinations, dilated pupils, suicidal and other harmful thoughts and/or actions, chest pain, extreme paranoia, delusions, and violent behavior.

Some drug policy reform advocates argue that the synthetic drug problem is a product of America's prohibitionist policy on marijuana. If individuals had legal access to marijuana, there would be no need to experiment with these dangerous synthetic substances, thus preventing overdoses, advocates say.

"It’s hard to imagine that if natural marijuana weren’t criminalized and stigmatized that so many people would choose a much more dangerous and untested synthetic alternative," Tom Angell, the founder of Marijuana Majority, told ATTN:. "This seems like just another health and safety reason to end marijuana prohibition ASAP."

RELATED: There's No Such Thing as Synthetic Marijuana