RALEIGH, N.C. (AP) — One of the world’s largest investment funds is dumping its shares in Duke Energy Corp. because it sees too much risk in what it called the largest U.S. electric company’s history of environmental damage, the fund’s managers announced Wednesday.

The arm of Norway’s central bank that manages the pension fund created by the Scandinavian country’s oil wealth said it has decided to bar investments in Charlotte, North Carolina-based Duke Energy. The fund has previously decided against investments in mining and coal-based energy companies, and makers of land mines, nuclear weapons and tobacco.

The company said it was disappointed but not surprised by the decision.

Norway’s Government Pension Fund Global is the third-largest public investment fund in the world behind the U.S. social security and Japanese national pension funds, according to the U.S.-based Sovereign Wealth Fund Institute.

An ethics advisory board in April recommended that fund-manager Norges Bank exclude investments in Duke Energy and three operating subsidiaries because the companies have “repeatedly discharged environmentally harmful substances” from pits at North Carolina power plants that store the waste left after decades of burning coal for power generation.

Environmental groups have sued Duke Energy, alleging pollutants including arsenic and cancer-causing hexavalent chromium have infiltrated into groundwater and rivers neighboring the plants.

North Carolina officials began pursuing stronger regulations and enforcement of coal ash in 2014 after a pipe burst at a holding pit at Duke Energy’s power plant in Eden, coating 70 miles of the Dan River on the North Carolina-Virginia border in more than 30,000 tons of sludge.

A state law adopted later that year required cleanup at all 14 power plants. While pits at half the plants must be excavated and moved, state lawmakers amended the law earlier this year to increase the possibility that Duke Energy will be allowed to cover the remaining sites in place. Republican Gov. Pat McCrory, who is seeking re-election this November, worked for the company for nearly three decades.

The Norwegian fund’s advisory council noted that Duke Energy’s coal-ash cleanup may not be completed for more than a decade. Utilities in Georgia, Virginia and South Carolina and elsewhere across the United States also have been forced to start cleanup efforts.

“We have made significant progress closing ash basins in ways that put safety first, protect the environment and minimize the impact to local communities,” Duke Energy said in a statement.

Duke Energy denies that the 112 million tons of coal ash in its storage pits are polluting water supplies. But it admitted to violations related to the Dan River spill when it pleaded guilty to federal pollution crimes in May 2015 and agreed to pay $102 million in fines and restitution, the state agency said.

North Carolina health regulators last year warned neighbors against drinking groundwater from their wells, citing the presence of hexavalent chromium, which can cause lung cancer when inhaled and which the Environmental Protection Agency says is likely carcinogenic when ingested. State officials retracted those warning letters earlier this year, saying the safety threshold was set so low it was out of step with other accepted limits for the heavy metal.

Norway’s Government Pension Fund Global ended last year with about 4.7 million shares of company stock, or about 0.68 percent of Duke Energy shares, the company said. The shares were then worth about $304 million, the fund’s annual report said. The fund remains a significant investor in the company, but exact ownership figures weren’t available, company spokeswoman Catherine Butler said Wednesday.

___

Follow Emery P. Dalesio at http://twitter.com/emerydalesio. His work can be found at http://bigstory.ap.org/content/emery-p-dalesio.