MADISON, Wis. (AP) — Four construction projects at state-run power plants dating to 1995 violated the Clean Air Act by increasing pollution without installing required controls, according to a state report.

A 2007 lawsuit filed by the Sierra Club raised questions about whether state officials were following the act's requirements to obtain permits for construction at state plants and install equipment to cut emissions. Under a legal settlement with the environmental group, the Department of Administration was required to check more than 25 projects dating back to 1995 for compliance.

The review, obtained this month by The Associated Press through an open records request, found three projects at Capitol Heat and Power in Madison and one at a plant in Waupun violated the act's requirements. The state is already moving to fix the violations at both plants by studying cleaner alternatives than coal to run them.

The study found all other projects were routine maintenance that would not have required permits and tighter controls. But that conclusion has drawn criticism from the Sierra Club, which claims the study was not thorough enough and that other plants remain in violation of the act.

In recent weeks, the Sierra Club has argued in public documents that plants at University of Wisconsin-Stevens Point, UW-Stout, UW-La Crosse and UW-Eau Claire should be required to install pollution controls. The Department of Natural Resources is reviewing the group's comments.

Sierra Club lawyer David Bender said Monday the state's review downplayed the scope of problems in the past. He said the review used a method to measure whether projects increased pollution that is not accepted by regulatory agencies and missed some pollution increases.

In other cases, the report did not give enough information to prove projects were routine and exempt from the act's requirements, he said.

Sierra Club spokeswoman Jennifer Feyerherm noted the group has the option of returning to federal court to enforce the settlement but stopped short of threatening to do so.

The Madison-based consulting firm RMT, Inc., a subsidiary of Alliant Energy, was paid $144,000 for the review, which is dated Dec. 31, 2008.

Department of Administration spokeswoman Linda Barth blasted the Sierra Club for questioning whether the state had done enough to fix its plants under the settlement.

"We find it very frustrating that the Sierra Club is more interested in creating a controversy where one does not exist to get a day's worth of headlines rather than return our good faith effort," she said.

She stood by the review, which identified the projects not in compliance as:

— a $6.75 million project to replace water pumps and pipes and add a new cooling tower at Capitol Heat, which powers the Capitol and other state office buildings. The changes increased fuel use and associated air emissions. Under a worst-case scenario, emissions of particulate matter, sulfur dioxide and other sources went up by more than 100 tons per year.

— a $720,000 replacement of controls on two boilers that increased their capacity at Capitol Heat.

— a $2.3 million addition of two new 800-ton chillers and related modifications to provide increased air conditioning capacity by 30 percent at Capitol Heat.

— a $1 million replacement of coal feeders at the Waupun Central Generating Plant, which powers a state prison. Potential emissions increased drastically as a result, the study found.

After the Sierra Club filed its lawsuit, a federal judge ruled in 2007 the Charter Street plant that powers University of Wisconsin-Madison was not in compliance with the Clean Air Act. In response, Gov. Jim Doyle pledged that plant and Capitol Heat would stop using coal.

The state is moving forward with a $251 million project to convert Charter Street to run on biomass, one of the largest such projects of its kind in the nation.

Consultants have recommended a $25 million upgrade to retire old coal equipment at Capitol Heat and switch to cleaner-burning natural gas. A study of Waupun completed last month recommended various options to reduce coal use and pollution.

RMT is also developing a checklist to be used by state employees to evaluate whether future projects trigger the Clean Air Act requirements, Barth said, and will be paid an additional $17,700 for that work.