Competing studies are under way to assess air pollution from Wisconsin’s frac sand industry, and the author of one said current state law isn’t protecting people well enough. A separate study, meanwhile, will examine the impact of frac sand mines on water.

Nearly a fifth of Wisconsin’s 70 active frac sand mines and processing plants were cited for environmental violations last year, as the industry continued to expand at a rapid clip.

A brief run-down of the permits required to open a frac sand mine or processing plant.

Wisconsin Public Television’s Frederica Freyberg will talk with University of Wisconsin-Eau Claire public health professor Crispin Pierce about the results of his study on air quality at mines around the state.

Dairyland and other Wisconsin coal-fired plants have begun lowering emissions, but not necessarily in response to demands by pollution regulators. Many of the changes have resulted from pressure and lawsuits brought by the nonprofit Sierra Club, which has campaigned for a decade to cut emissions from coal combustion. But enforcement is inconsistent, and some residents living in the shadow of coal plants are concerned their health may be affected.

A state program helped Didion Milling win $5.6 million in stimulus funding to expand its Cambria milling and ethanol plant, which has a history of environmental violations.