Enbridge Energy Partners LP was formed in 1991. The Company owns and operates crude oil and liquid petroleum transportation and storage assets, and natural gas gathering, treating, processing, transportation and marketing assets in the United States of America. The Company provides services to its customers and returns for its unit holders mainly through the following activities: Interstate pipeline transportation and storage of crude oil and liquid petroleum; Gathering, treating, processing and transportation of natural gas and natural gas liquids, through pipelines and related facilities; and supply, transportation and sales services, including purchasing and selling natural gas and natural gas liquids. It conducts its business through three business segments: Liquids, Natural Gas and Marketing. The Company's Liquids segment includes the operations of its Lakehead, North Dakota and Mid-Continent systems. These systems consist of FERC-regulated interstate crude oil and liquid petroleum pipelines. The Mainline system serves all the refining centers in the Great Lakes and Midwest regions of the United States and the province of Ontario, Canada. The System serves all the refining centers in the Great Lakes and Midwest regions of the United States and the Province of Ontario, Canada. The Company's Natural Gas segment consists of natural gas and natural gas liquid, gathering and transportation pipeline systems, natural gas processing and treating facilities and natural gas liquid fractionation facilities, predominantly located in active producing basins in east and north Texas, as well as the Texas Panhandle and western Oklahoma. The Company's marketing segment provides natural gas supply, transportation, balancing, storage and sales services for producers and wholesale customers on its natural gas pipelines as well as other interconnected natural gas pipeline systems. The Company's operations are subject to complex federal, state and local laws and regulations relating to the protection of health and the environment, including laws and regulations that govern the handling, storage and release of crude oil and other liquid hydrocarbon materials or emissions from natural gas compression facilities.