The Oil Spill Liability Trust Fund is a trust fund managed by the federal government and financed by a per-barrel tax on crude oil produced domestically in the United States and on petroleum products imported to the United States for consumption. The fund was created in 1986, but use of the fund was not authorized until the Oil Pollution Act's passage in 1990. The funds may be called upon to cover the cost of federal, tribal, state, and claimant oil spill removal actions and damage assessments as well as unpaid liability and damages claims. No more than one billion dollars may be withdrawn from the fund per spill incident. Over two decades of court cases have demonstrated that obtaining funding from the Oil Pollution Spill Liability Fund can be a difficult task.