LANSING, Mich. -

Michigan Gov. Rick Snyder has signed bills banning so-called synthetic marijuana.

A signing ceremony was held Tuesday in Lansing.

The substance, sold under trade names like Spice and K2, has been available in stores as a mix of dried herbs and spices sprayed with chemicals. It has been blamed for health problems and violent behavior, especially among young people.

The bills crack down on synthetic cannabinoids and products sometimes referred to as bath salts. They also allow the Department of Community Health to declare health dangers when other synthetic drugs pop up. The bills were recently approved by the state Legislature.

Some counties and communities already have acted on their own to ban synthetic marijuana.

The National Conference of State Legislatures reports that at least 40 states have banned synthetic cannabinoids.

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