With tax filing season getting underway this week, certain industries and taxpayers are still waiting for Congress to act on a slate of expired tax breaks, left out of last year’s sweeping tax code overhaul and now mired in a sticky debate over spending and immigration.

The result is that affected stakeholders, ranging from homeowners upside down on their mortgages to biodiesel fuel producers, can’t fully share in the $1.5 trillion tax cut’s largesse touted by President Donald Trump in Tuesday night’s State of the Union address as “tremendous relief for the middle class and small businesses.”

Senate tax writers have filed legislation to extend more than 30 targeted provisions that lapsed at the end of 2016, but top House Republicans have expressed less interest in taking up the package, and under the Constitution, all revenue bills must originate in the House. Thus the tax “extenders,” like other leftover items from last year, have remained on ice as party leaders negotiate a broad immigration, border security and long-term budget deal.

The result is that some individuals won’t be able to claim certain breaks on their 2017 returns due in April, which the Internal Revenue Service began accepting as of Monday. That includes a deduction of up to $4,000 for qualified tuition and related expenses, claimed by about 1.7 million households on their 2015 returns.

Lawmakers and industry groups expect tax extenders to hitch a ride on a final spending package in the coming weeks or months. But those broader negotiations are proceeding at a snail’s pace, and with tax filing season underway, advocates for renewing the targeted tax perks are ramping up their push.

Senate Finance Chairman Orrin G. Hatch filed the Senate bill in December to renew most of the expired tax breaks for two years, through 2018. His House counterpart, Ways and Means Chairman Kevin Brady, has made clear his disdain for the extenders process but indicated the issue is on the table in the spending and immigration talks.

As those negotiations drag on, holding up most other policy debates in Congress, some Senate tax writers sound less than optimistic about the fate of Hatch’s package.

Watch: Lawmakers Praise Trump in Rose Garden Tax Bill Celebration

‘Promises are cheap’

“I don’t want to be pessimistic about it. We’ve done it every time it needed to be done in the past, and I expect that it’ll be done again. But you know, we’ve been promised, and promises are cheap in this town,” Iowa Sen. Charles E. Grassley said last week on local radio station WNAX.

Grassley, a senior Finance Republican and the panel’s former chairman, said House Speaker Paul D. Ryan personally assured him that an extenders package would move separately from last year’s historic GOP tax code overhaul, which left out many favored tax breaks. Lapsed provisions such as the biodiesel blenders credit are critical for many of the Iowa senator’s constituents.

“It was decided not to include them, based on the promise to a lot of us … that there’d be an extenders bill and we’d get the extenders bill passed,” Grassley said. “It included a conversation that I had by telephone with Speaker Ryan, because my vote was necessary to get the bill out of Finance Committee, that the House would be acting on an extension bill as well.”

A spokeswoman for Ryan did not respond to questions about whether the House will take up a tax extenders measure.

Meanwhile dozens of business, energy, agriculture and housing organizations sent a letter to top tax writers in Congress last week arguing that allowing the provisions to lapse has “negatively impacted businesses and individuals that make important planning decisions based on tax policy.”

“Every day that these provisions remain lapsed creates further confusion and uncertainty for taxpayers, while needlessly undermining economic growth and job creation in the private sector,” the groups wrote.

Homeowners, rum producers

The expired provisions include payments to rum producers in Puerto Rico and the Virgin Islands from excise tax revenues; credits for railroad maintenance, Native American employment, mine rescue team training and more.

The National Association of Realtors and the National Association of Home Builders, two groups that threw their weight around during the tax overhaul debate, were among the organizations calling on Congress to renew the extenders.

The Realtors and home builders have pushed to extend a tax break for mortgage debt forgiveness, which enables homeowners to avoid tax on “phantom” income created under restructuring arrangements with lenders, and another expired deduction for private mortgage insurance premiums. The last short-term extension of those write-offs was projected to cost the government nearly $7.5 billion in revenue, according to a Joint Committee on Taxation estimate of legislation that renewed the provisions for two years through 2016.

Special expensing rules for film, television and theater productions that expired at the end of 2016 would be extended retroactively for 2017 under the Senate measure. That break was actually addressed in the tax overhaul last year — it was renewed effective at the start of 2018 — but without action by Congress it would not be in effect for the current filing season.

The horse- and car-racing industries each have a favored provision expiring: one that allows owners to write off the cost of a racehorse over three years, rather than up to seven, and another that allows construction and renovation costs for motorsports complexes to be deducted over an accelerated depreciation schedule.

A swath of energy-related tax breaks is also at stake, including credits for certain wind energy facilities, geothermal heat pumps, fuel cell projects, hybrid solar lighting and more.

Koch brothers’ opposition

Other outside groups have weighed in against tax extenders, including the network of conservative organizations backed by the billionaire Koch brothers.

Americans for Prosperity and Freedom Partners also sent a letter to Congress last month asking them not to renew the tax breaks they said are “claimed almost exclusively by powerful and well-connected special interests.”

“Including this corporate welfare in any deal would be a significant and disappointing step backwards that would weaken historic tax reform just weeks after it was passed,” they wrote.

Meanwhile, the Petroleum Marketers Association of America has opposed one specific portion of Hatch’s extenders bill: a retroactive renewal of the oil spill liability fee, a 9 cents-per-barrel tax on crude oil at the refinery gate, which supplies a roughly $5.8 billion U.S. Coast Guard trust fund used for containing and cleaning up oil spills.

The fee, enacted after the Exxon Valdez oil spill in 1989, was allowed to lapse at the end of December. Hatch has proposed extending it through 2018, retroactive to Jan. 1, a move that the association said would cause confusion in the petroleum supply chain.

“Some wholesale petroleum marketers have indicated to PMAA that they are caught between a rock and a hard place if they buy fuel from suppliers who continue to charge this fee because dealers at the retail level are aware of the expiration of the fee and are refusing to pay the fee,” the association wrote in a policy brief last month. “Therefore, some wholesalers are forced to eat this fee for now to satisfy the customers’ demand. If the tax were to be reinstated retroactively, wholesale petroleum marketers are unlikely to recoup the losses.”

The government is currently funded through Feb. 8 under a short-term stopgap. The next spending bill due by then is likely to be another continuing resolution, rather than a full spending package carrying tax extenders and other policy items, but it’s possible sweeteners like extenders could also be added to the CR to ensure its passage through Congress.