North America's offshore areas that are closed to drilling hold some 135 trillion cubic feet (Tcf) of natural gas and 30 billion barrels of oil, the Interstate Oil and Gas Compact Commission concludes in a recent report. The estimated technically recoverable oil and gas resources in these restricted areas represent an amount comparable to the current proved reserves of the U.S. The report was prepared by the North American Coastal Alliance, a work group of the IOGCC. Off-limit areas were defined as land not open to exploration and development, either through legislation or policy. In the U.S., this area includes the North Aleutian Basin offshore Alaska; the offshore Atlantic; portions of the offshore eastern Gulf of Mexico; the Great Lakes; and unleased acreage offshore California, Oregon and Washington. The Atlantic offshore ranks highest in potential, containing estimated undiscovered resources of 33 Tcf of gas and 3.4 billion barrels of oil. Some 245 million acres of land, stretching from Maine to Florida, are withdrawn from leasing due to government moratoria. Canadian regions under restrictions include the west coast of British Columbia; portions of northern Canada; and Georges Bank, offshore Nova Scotia. British Columbia holds far and away the greatest potential for undiscovered resources: studies indicate the province's offshore Queen Charlotte, Winona, Tofino and Georgia basins could host 41 Tcf of gas and 9.8 billion barrels of oil. As for land offshore Mexico, this was not considered in the analysis. "If potential resources in areas that have been withdrawn from leasing or are under moratoria could be developed, they would play an important role in meeting future North American energy requirements," the IOGCC reports. "It is important for citizens and policy-makers to understand the significance of these potential North American oil and gas resources when making energy development decisions." Production from offshore accumulations is a crucial component of North America's energy supply. At present, offshore production from the Outer Continental Shelf of the Gulf of Mexico and California supplies 29% of U.S. oil production and 21% of domestic gas production. The eastern Canadian offshore contributes 10% of that country's oil production, and 2% of its gas production.