The Donald C. Cook Nuclear Plant, Units 1 and 2. CREDIT: Nuclear Regulatory Commission/Flickr A cooling system attached to a nuclear power plant in southwest Michigan was steadily spilling oil into Lake Michigan for about two months, the Detroit Free Press reported Saturday. Approximately 2,000 gallons of oil from a cooling system at the Donald C. Cook Nuclear Plant leaked into the lake last year, according to an event notification posted on the Nuclear Regulatory Commission website. The leak started on October 25, and was isolated on December 20, the report said. Plant officials reportedly notified the State of Michigan of the leak on December 13. Bill Schalk, communications manager for the Cook Nuclear Plant, assured the Detroit Free Press that there would be no impact on the lake. “One of the first things we did when we looked at the potential for a leak is examine the lake,” he said. “Oil floats on top of the water and you see a sheen, but we could find no evidence of oil in our reservoirs, in the lake or on the beach. It has been dispersed.” Others disagree that just because the oil is dispersed, there no threat to the lake and its ecosystems. Michael Keegan, director of the nonprofit Coalition for a Nuclear-Free Great Lakes, lamented that the oil would not be recoverable, and questioned whether plant officials truly knew how much oil had spilled into the lake, considering they didn’t know the leak had been happening for two months. “What’s concerning is they don’t really know the extent of the leak,” he said. “Nearly two months later is the first determination they make that they have an oil leak? It speaks to the quality assurance of all of their other systems.” Lake Michigan is the second-largest of the Great Lakes by volume, and the only one located entirely in the United States. The EPA describes Lake Michigan, seemingly unironically, as “a source of drinking water, as a place for swimming and fishing, as a scenic wonderland, and as a sink for municipal and industrial waste and runoff from the surrounding lands.” Though it may seem counter-intuitive, small oil leaks at nuclear power plants are fairly common, usually coming from power generators. Approximately 70 gallons of oil leaked out of a power transformer at the Palisades Nuclear Power Plant in Michigan this past May. The Beaver Valley nuclear plant in Pennsylvania spilled five gallons of oil into the Ohio River this September. And in February 2013, the Susquehanna nuclear power plant was temporarily shut down after a small hydraulic oil leak. The Cook Nuclear Plant itself had been suspected of spilling 8,700 gallons of oil this past August, but plant officials told the Nuclear Regulatory Commission that an employee had just made an error when reading the level of oil in a diesel generator. While arguably every instance of hydrocarbon pollution into the Great Lakes is of concern to environmentalists, oil from nuclear plants are not usually their main focus when it comes to oil contamination. The Great Lakes provide drinking water to more than 40 million people and contain nearly 20 percent of the world’s surface freshwater, and environmentalists say one of the biggest oil-related threats are aging oil pipelines that run below the Straits of Mackinac, directly between Lake Michigan and Lake Huron. Every day, about 23 million gallons of Canadian tar sands crude oil pass through the Straits of Mackinac in the pair of 61-year-old underwater oil pipelines owned by Enbridge, according to the Free Press. Tar sands oil is harder to clean up than conventional oil, mainly because it does not float on top of water like conventional crude. Instead, it gradually sinks to the bottom, making normal cleanup techniques and equipment of little use. And because tar sands oil needs chemicals like benzene to liquefy it, those chemicals evaporate into the air while the oil sinks. Just two weeks ago, a pinhole-sized leak was discovered in one of the two Enbridge pipelines under the Straits of Mackinac, raising questions about their integrity and reviving worry about a large spill. Other threats to the Great Lakes include invasive species, polluted industrial and agricultural runoff, and climate change. The post A Nuclear Plant Leaked Oil Into Lake Michigan For Two Months Straight appeared first on ThinkProgress.