The lingering effects of Hurricane Ivan and the refinery shutdowns it triggered are most directly causing the higher prices you're seeing when you fill up. Locally, the average price of a gallon of unleaded gas hit $2 in Northern Kentucky on Tuesday - the highest price since June 8, according to the Oil Price Information Service.

Tuesday's average price in Southwest Ohio was $1.95, also the highest since early June.

Prices in both areas were slightly higher than the national average of $1.90, the service said.

Diesel prices also are being driven up because of Ivan's aftereffects. A new U.S. Department of Energy's weekly survey shows the national average price for a gallon of diesel was $2.01the highest of 2004. The average price in the Midwest was $1.98.

"Short-term expectations in the market anticipate pump postings will eclipse that mark and move to new highs in states across the country," the information service said.

Crude oil rose above $50 a barrel to a record in New York on concern that rebels may attack oil fields in Nigeria, Africa's biggest producer of the fuel, at a time when U.S. inventories are close to a 29-year low.

Light crude for November delivery rose 26 cents to $49.90 to a new settlement high on the New York Mercantile Exchange after trading as high as $50.20.

Crude has risen 15 percent in nine straight days of increases, the longest run of gains since August 2002.

Homeowners and energy-intensive industries could feel the sting from high oil prices worsen as seasonal demand picks up this winter.

The 75 percent increase in the price of oil in the past year also promises to heat up as a political issue, with just over a month until the presidential election.

Crude futures first hit $50 a barrel in after-hours trading late Monday, spurred higher by reports that rebels in Nigeria continue to battle for control of the vast southern oil fields in the world's seventh-largest exporter. Nigeria ships oil with a low sulfur content, which makes it easier to refine into gasoline. It supplies 10 percent of America's supply of crude.

A unit of Royal Dutch/Shell Group, which accounts for roughly half of Nigeria's daily production of 2.5 million barrels, said Tuesday that insecurity in the region forced it to shut an oil flow station in the Niger Delta that pumps 28,000 barrels a day. Also on Tuesday, Saudi Arabia pledged to boost the limits of its daily oil production by a half-million barrels, bringing its output capacity to 11 million barrels, but the move failed to calm markets.

Meanwhile, daily oil output in the Gulf of Mexico - home to a quarter of U.S. oil production - remains about 500,000 barrels below normal two weeks after Ivan, the U.S. Minerals Management Service said.

Adjusting for inflation, prices are still about $30 a barrel below the level reached in 1981 after the Iranian revolution. Even so, the United States is on pace to spend an extra $68 billion on oil this year, or 30 percent more than was spent last year. That calculation is based on analysts' estimates of an average oil price of $40-per-barrel in 2004, compared with $31 in 2003, as well as slightly higher demand.

This year's surge in prices has resulted in "a major redistribution of income from oil consumers to oil producers" and has been a drag on the economy, according to Nigel Gault, an economist at Global Insight.

Higher energy costs could hurt company earnings, depress stock markets, curtail consumer spending and eventually slow growth. Analysts usually expect a $10-a-barrel increase in oil prices to shave off 0.3 to 0.5 percentage points in gross domestic product growth.

Not everyone is convinced oil prices can stay high for too long. "Oil prices don't exist in a vacuum," said Daniel Yergin, chairman of Cambridge Energy Research Associates. "People generally underestimate the feedback effect on the economy. Markets adjust. The question is do they do it smoothly or painfully."

The Associated Press, Bloomberg News and the New York Times contributed to this report.