The spending bill signed into law Friday by President Trump includes language that reinstates a tax on each barrel of oil to assist in spill cleanups.

The 9-cents-per-barrel tax applied to domestic and imported barrels before it expired at the end of 2017. But the spending bill extended it for another year, until Dec. 31, 2018, and will take effect again starting March 1.

The funds collected will go toward the Oil Spill Liability Trust Fund. The oil tax is the main contributor to the fund, which is used to pay for cleanup in the event of an oil spill, such as the BP Deepwater Horizon spill in 2010.

According to the Congressional Research Service, this tax generated an average annual revenue of $500 million.

The tax was not renewed at in December, which caused a short lapse around the end of the year, but that lapse garnered criticism from lawmakers and environmentalists.

“The Oil Spill Liability Trust Fund ensure that when there is a spill, American taxpayers are not left holding the bag to clean up Big Oil's mess," Sen. Ed Markey, D-Mass., said in a statement after the tax was not renewed. "We should have a robust trust fund — not just trust that oil companies will do nothing wrong — in case a disaster like the BP spill happens again."