“An upswing in regulatory activity in not unexpected given the field’s rapid expansion,” he said. “It’s likely we’re seeing a little bit of inexperience on the part of some new or smaller operators.”

WISA is a statewide organization that says it promotes safe and environmentally sound mining practices. One of the organization’s member companies, Smart Sand, is cited in the report for violations.

Budinger said the report highlights the importance of his organization’s work. He said that all of WISA’s members follow a strict code of conduct.

Budinger also said his organization supports fair and science-based regulation as well as strict enforcement of breaches of regulations.

“When someone in our industry gets a violation, it hurts all of us,” he said.

The number of frac sand facilities in Wisconsin increased more than tenfold within the last four years, growing from 10 in 2010 to 135 in 2014. To keep up with the boom, the state DNR hired two new environmental compliance engineers to monitor air quality, inspect mines and keep an eye on their operations.

Tanner Connors, one of the DNR’s new hires, said he’s not seen many violations since the air quality monitoring program kicked off in July.