A potential tax write-off for homeowners with crumbling foundations is potentially at risk in Congress.

Democratic Sens. Richard Blumenthal and Chris Murphy were attempting Thursday to amend the Republican Senate tax bill, which abolishes the tax deduction for property casualty losses except those stemming from federally declared disasters.

Homeowners learned last week that the Internal Revenue Service had agreed that taxpayers with foundations deteriorating because of the presence of an iron sulfide can deduct 75 percent of their unreimbursed repair costs from their federal taxes as a casualty loss.

Blumenthal says it’s unclear if his and Murphy’s amendment restoring the deduction will be called.

He says there’s a chance homeowners can claim the deduction if they have written proof of a loss by the end of the year.