A joint hearing of Assembly and Senate mining committees examined legislation Monday that would exempt existing frac-sand mines in Wisconsin from adhering to new rules issued by local governments.

Sen. Tom Tiffany, R-Hazelhurst, and Rep. Joan Ballweg, R-Markesan, answered questions about their bill at the hearing and argued the legislation would prevent local governments from running existing mining companies out of business with excessive regulations.

Democrats and environmental advocates opposed to the Republican-backed bill have raised concerns the bill would tie local officials’ hands in regulating the rapidly expanding mining industry in Wisconsin, despite a lack of clarity regarding the potential health effects involved in sand mining.

“What worries me about this bill is that it restricts local government to issue-reactionary measures in light of new health and safety findings. Why would we want to do that?” Rep. JoCasta Zamarripa, D-Milwaukee, said.

Tiffany and Ballweg told Democrats in light of new evidence of negative health and environmental impacts of sand mining, the Department of Natural Resources and the Environmental Protection Agency would have the authority to step in and take action.

Tiffany also said there is no direct evidence that sand mines trigger increases in rates of lung disease.

“The notion that this is the Wild West is just not the case. This is a highly, highly regulated industry,” he said.

Rep. Kevin Petersen, R-Waupaca, said the bill has sweeping implications and urged lawmakers to consider all the possible effects as the bill moves forward. Petersen also said the bill raises environmental and regulatory issues.

Tiffany said the bill is actually a very simple one and seeks only to “grandfather in” current restrictions for current frac-sand mines.