As you fill your tank for Labor Day weekend, you could say that oil industry CEOs are a pain in your pump.

Only 18 months ago, you could buy gas for less than $1.75 a gallon. Now the price hovers around $3. Americans will shell out $200 billion more on gasoline this year than in 2004.

The CEOs of our country's 15 biggest oil companies are surfing the wave of inflated oil prices all the way to the bank.

A new study by United for a Fair Economy and the Institute for Policy Studies (which I co-authored), reveals that in 2005, the Big Oil 15 were paid an average salary of $32.7 million, three times the already excessive pay of CEOs in comparably size businesses.

Between 2004 and 2005, Big Oil barons got a 50 percent raise.

CEO William Greehey of Valero Energy was the industry's top pump profiteer in 2005, collecting $95.2 million. It would take the average oil industry construction worker 4,279 years to earn what Greehey banked in just one year.

A close second was CEO Ray Irani of Occidental Petroleum, at $84 million. With that paycheck, Occidental, on an industry-average salary of $43,450, could employ 1,932 rotary drill operators.

Surging Big Oil salaries were limited to top managers, as average workers saw little gains.

The gap between Big Oil CEOs and average oil and gas industry workers is a dizzying 511 to one, while the national CEO-average worker ratio is 411 to one.

ConocoPhillips CEO James Mulva defended the high pay. "Obviously, these are very, very large numbers," he acknowledged as part of a Big Oil public relations appearance on ABC's "Good Morning America." "But on the other hand, if you look at the oil companies, the international oil companies, there are huge responsibilities with respect to asset bases and hundreds of billions of dollars."

Mulva, whose personal paycheck almost doubled in a year — from $16.1 million in 2004 to $31 million in 2005 — is essentially saying: "We're worth it." But that doesn't explain why U.S. oil executives are so much more precious than CEOs of other global oil companies.

BP (British Petroleum) and Royal DutchShell, the world's second- and third-largest oil companies, respectively, operate in the same global market. Yet their CEOs are paid only one-eighth of their U.S. counterparts. BP's Lord John Browne was paid $5.6 million in 2005 and Shell's Joeron van der Veer collected $4.1 million.

When called before congressional committees to explain skyrocketing fuel prices, some U.S. oil executives explained that the situation was beyond their control, pointing their fingers at global supply and demand, weather disasters and environmental regulations.

Yet when asked to justify their bulging CEO paychecks, 50 percent raises and windfall retirement packages, they assured watchdogs their compensation is fair because of their performance in boosting company profits. ExxonMobil saw a second-quarter profit of $10.36 billion, the second-biggest quarterly profit in history, exceeded only by their own previous quarter.

But if the escalating oil prices are the result of global forces outside of company control, then these CEOs are reaping an unearned windfall at our expense.

And if they truly are performing at a standard three times higher than other U.S. CEOs, perhaps they should be held to account for their failure to plan or make investments to reduce our country's dependence on foreign oil.

A bipartisan group of U.S. senators has recently proposed instituting a windfall tax on oil industry profits that are not reinvested in energy conservation or expanded capacity. Revenue could be directly rebated to consumers or channeled into public investments to reduce dependency on oil.

Big Oil has blocked such proposals in the past and has used its campaign contributions and political muscle to stymie development of a sane energy policy. But the moves to address climate change, stop consumer price gouging and limit Big Oil's political power could mean its days are numbered.

Until that happens, though, Americans must brace themselves for more pain at the pump.

Chuck Collins is a senior scholar at the Institute for Policy Studies and co-founder of United for a Fair Economy.