U.S. Sen. Olympia Snowe, R-Maine, was elected to the U.S. House of Representatives in 1978, then to the Senate in 1994.

She is ranking member of the Senate Committee on Small Business and Entrepreneurship, and a member of the Senate Finance Committee, the Commerce, Science and Transportation Committee and the Select Committee on Intelligence. Her top donors reflect her Maine ties and committee assignments.

In compiling its top contributors list, the nonpartisan Center for Responsive Politics reviews federal campaign finance reports and total donations from individual companies’ employees, as well as any political action committees they create. PACs are groups organized to fundraise and advocate on behalf of political causes.

The O’Hara Corp., of Rockland, owns and operates a marina, provides a boat transport service, builds boats, sells bait and operates three fishing trawlers off the Alaskan coast. Snowe oversees fishing as ranking member of the subcommittee on Oceans, Atmosphere, Fisheries and the Coast Guard, a part of the commerce committee.

Aetna Inc. is a nationwide health insurer that accounts for 10 percent of the Maine market, according to the Center for American Progress, a liberal think tank based in Washington, D.C.

Snowe played a pivotal role in negotiating health care reform, which emerged from the powerful finance committee and has sweeping impacts on insurers as well as the federal entitlement programs.

General Dynamics is a shipbuilding defense contractor that owns Bath Iron Works, one of Maine’s largest employers. Snowe, in the Maine political tradition, works to promote BIW’s interests in Washington.

Applied Thermal Sciences Inc. is an engineering research and development company based in Sanford that contracts with the federal government and private industry. In 2007, the company won a $14.5 million, three-year award from General Dynamics/Bath Iron Works for producing hybrid laser welded panels for the U.S. Navy DDG 1000 destroyer.

New York Life Insurance is the biggest mutual life insurer in the country and spends millions each year lobbying Congress on taxes, trade and retirement policy, according to the Center for Responsive Politics. Snowe influences those policies on the Senate Finance Committee.

General Dynamics and New York Life Insurance are on the Center for Responsive Politics’ “Heavy Hitters” list, which catalogs the top all-time campaign donors from 1989-2010.

Dave Levinthal, spokesman for the center, said while many senators, particularly those from small states, rely almost exclusively on out-of-state money, Snowe’s top donors buck that trend.

“Indeed, at least among her top donors, they’re a bit more homegrown than some senators have,” he said.

A bit more than half, 54 percent, of Snowe’s total campaign donations since 1989 have come from individuals, versus 36 percent from political action committees.