DENVER -- A new study spells out some of the costs of illegal immigration here in Colorado.

The report was put out Tuesday by a group that wants to put a measure limiting state services to illegal immigrants on the November ballot.

But not everyone buys into the results of the study, saying it's biased and it simply doesn't add up.

One such group that disagrees with the study is a humanitarian center that matches up day laborers and employers. Their view of the impact of undocumented workers differs from the report.

The exact number of illegal immigrants in the state is blurry, but the impact they are having on the state and local budgets is clear, according to the organization Defend Colorado Now.

"This illegal immigration needs to be brought under control," said John Andrews, the group's co-chair. "This is not just a problem, it is a crisis."

The group's data claims that Colorado taxpayers spent $64 million a year on Medicaid for illegal immigrants, $61 million a year to take care of them in prison, and $899 million a year to educate their children, with the total cost adding up to $1 billion.

"That's $1 billion out of the pockets of Colorado taxpayers this year because of the failure of the federal government to enforce secure borders," said Andews.

But the director of a day-laborer hiring center said that's just one part of the story. She argued that undocumented immigrants provide a lot of positives to our society, too.

"They're not actually thinking about what kind of extra economic benefit that these immigrants are bringing to our economy in Denver," said Minsun Ji, the executive director of Centro Humanitario. "I believe that all those figures are coming from the fear of seeing new immigrants."

The study also shows that illegal immigrants in Colorado cost the country $2 billion in lost or lower wages. Defend Colorado Now said its initative, if it passes in November, would encourage illegal immigrants to go elsewhere, and that would lower the state's overall cost.

Meanwhile, state senators passed an immigration measure on Tuesday. It increases the fines for those who provide illegal immigrants with phony identification. Providing fake documents will now cost criminals up to $50,000.