A new law banning the sale of synthetic marijuana went into effect in Chicago Wednesday. Businesses caught selling fake pot will face fines up to $1,000. They could also have their business license revoked by the city.

Alderman Edward Burke said the ordinance closes a legal loop hole because the substance is dangerous.

“The fact that to this point these products have remained legal and readily accessible has created an illusion that they are safe. They clearly are not safe,” Burke said.

Meanwhile, Illinois Attorney General Lisa Madigan said a similar state law will go into effect on Jan. 1.