Cook County has begun charging a controversial $25 tax on every gun purchased in the county's suburbs.
The tax, which took effect Monday, is expected to raise about $600,000 this year.
Cook County Board President Toni Preckwinkle proposed the levy as part of her $2.9 billion budget, saying it'd be a way to make up some of the costs of gun violence.
"Gunshot victims make up more than 30 percent of the patients our trauma center sees," Preckwinkle said in a statement released Monday. "I know this tax will not unilaterally solve the violence issue we face here in Chicago and other parts of Cook County, but it is without a doubt a necessary piece of the puzzle."
But the new tax, which only applies to guns bought outside the city of Chicago, isn't without controversy.
Last month, a group of local gun shops and gun owners sued, saying the new tax violates the right to bear arms.
The suit argues there is no link between legal gun purchases and criminal activity.
Preckwinkle's spokeswoman, Kristen Mack, said county officials are confident the special tax will withstand legal challenge.
"When we proposed this tax in the fall, we expected it to be contentious," Mack said in a statement. "President Preckwinkle maintains she won't make decisions on the basis of whether or not somebody is going to sue the county, otherwise we'd never make bold proposals."