The rebuilding of parts of Texas and potentially Louisiana after Hurricane Harvey may be the most expensive disaster relief effort ever, with early projections of federal aid soaring to $150 billion and raising the prospect of several congressional actions to pay for it.

Texas Gov. Greg Abbott, a Republican, said Wednesday he thinks federal aid in the wake of Hurricane Harvey should top what was provided after Hurricane Katrina hit New Orleans in 2005 and Superstorm Sandy struck the Northeast in 2012.

Congress approved about $120 billion in long-term relief after Katrina, according to the Congressional Research Service.

The uncertainty about the cost of rebuilding after Harvey becomes another unresolved issue for lawmakers returning to work Sept. 5 after an August recess. Congress also faces decisions about the debt limit and fiscal 2018 spending before the end of September.

President Donald Trump has thus far not said how much the administration would request, saying only that it would be costly. “Probably there’s never been anything so expensive in our country’s history,” he said Tuesday in Austin. “There’s never been anything so historic in terms of damage and in terms of ferocity.”