SPRINGFIELD, Ill. (AP) — Illinois lawmakers are weighing legislation to prevent synthetic marijuana manufacturers from dodging laws banning the substance.

The Chicago Tribune reports that the state Senate passed a measure this week to ban all types of synthetic cannabinoids instead of just specific formulas. The bill is now in the House for consideration.

The effort comes after public health officials recently reported that a fourth person in Illinois has died after using synthetic cannabinoids authorities believed were laced with rat poison.

Synthetic cannabinoids are a man-made mixture of chemicals affecting the same brain cell receptors as THC, the psychoactive component in marijuana. The substance is often sold and branded as “Spice” or “K2.”

Illinois has passed several laws to ban synthetic marijuana, but manufacturers often change the formula to skirt the rules.

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