Several new forms of synthetic marijuana would be banned in Texas, with penalties for possessing, selling or making the drugs ranging from a misdemeanor to felony, under a bill passed Wednesday by the state Senate. The chemicals mimic the main ingredient in organic marijuana and are often sprayed on herbs sold to be burned as incense or smoked.

The drugs have become popular with teens, particularly in Texas, who can buy them under brand names such as K2, Spice, Genie and Fire & Ice.

But experts warn they also can be very dangerous, with side effects including hallucination, elevated heart rates and blood pressure, chest pains, blackouts and seizures. The Texas Poison Center Network reported receiving more than 550 calls related to the drugs in 2010.

“K2 is dangerous,” said Sen. Florence Shapiro, the Plano Republican who sponsored the bill. “There’s no beneficial or legitimate use of these products. We don’t know what it can do.”

The bill now goes to the House, where a similar measure in pending. If ultimately passed into law, Texas would join 16 other states with bans on synthetic marijuana. Shapiro has said the Texas measure would be among the toughest in the country.

The Senate bill would make the manufacture and sale of the drugs a felony. The penalty for possession would track current law covering marijuana, with a misdemeanor for having small amounts and larger amounts resulting in felony charges and a possible prison sentence.

Researchers developed synthetic cannabinoids, as scientists refer to the compounds, to test on mice as early as the 1970s. In recent years, though, producers have developed new compounds and sold them in tobacco shops, gas stations and online. Some web sites brag their form of K2 is not covered by any state bans and is “guaranteed to satisfy.”

Shapiro said she was shocked to learn middle and high school students could walk to stores near their schools to buy it.

“What we’re trying to do here is very simple: Get it out of the stores, get it out of their hands,” Shapiro said.