 The University's research concluded that taconite tailings from the western side of the Iron Range were safe for use in road construction, unlike the by-product from the eastern side of the Range, which had been linked to an increased risk to cancer.Tinklenberg reiterated that he would only support the sustainable use of western Iron Range taconite tailings as long as the research showed it to be a safe practice.Tinklenberg was also accused by congressional opponents, including Bob Olson of the Democratic-Farmer-Labor party, of not complying with lobbying registration regulations.