Fueled by employer and labor union lobbying, Congressional support to repeal the health care reform law's highly unpopular 40% excise tax has grown rapidly in recent weeks, but the push faces several obstacles.

Coincidentally, the effort comes as a study by the International Foundation of Employee Benefit Plans released this month found that nearly 60% of employers and other health care plan sponsors expect to trigger the 40% tax on the portion of premiums above $10,200 for individual coverage and $27,500 for family coverage.

Of those employers expecting to trigger what is known as the Cadillac tax, roughly 40% are changing their health plans to avoid it and a nearly equal percentage plan to do so before 2018, when the tax is to go into effect, according to the survey.

As employers work to avoid the tax mandated by the Patient Protection and Affordable Care Act, lobbying has intensified in Congress and had some success.

For example, the House Ways and Means Committee approved a measure in September to repeal the tax as well as penalties on employers for not offering health coverage and individuals for not having it.

Those provisions were in a broader so-called budget reconciliation bill approved late last week by the House Budget Committee and headed soon for a vote by the full House.

In addition, sponsorship for a repeal bill, H.R. 2050, introduced by Rep. Joe Courtney, D-Conn., has grown to 160.

In the Senate, where repeal interest once was limited to Republicans, Sen. Sherrod Brown, D-Ohio, has introduced a repeal bill, S. 2075, whose supporters include presidential candidate Bernie Sanders, an independent senator representing Vermont.

Another presidential candidate, Hillary Clinton, last month also encouraged “Congress to repeal the so-called Cadillac tax.”

Joining them was House Ways and Means Committee Chairman Paul Ryan, R-Wis.

“Congressional interest in repeal is very keen and very bipartisan,” said James Klein, president of the American Benefits Council in Washington.

“In a single week you have Hillary Clinton and Paul Ryan both calling for repeal,” said Mr. Klein, who also is a member of business-labor coalition, Alliance to Fight the 40, seeking to repeal the excise tax.

“There is no doubt there is significant support in Congress for repeal,” said Geoff Manville, a principal at Mercer L.L.C. in Washington.

Employers say one of the intended justifications for the tax — that it will reduce health plan costs — is a myth.

“Just because a penalty is imposed doesn't mean costs are controlled. How will an excise tax, for example, control soaring prescription drug costs?” said Sharreen Boone, director of benefits and compensation at home builder J.W. Homes L.L.C. in Smyrna, Georgia.

Unions also oppose the tax.

Labor urges repeal

Referring to the bipartisan repeal bill introduced in the Senate, Terry O'Sullivan, general president of the Laborers' International Union of North America, said in a statement that “we commend the senators' leadership and look forward to working with them and the rest of the Congress to ensure that workers across the country will be able to keep their health care and not have to pay this regressive tax.”

Whether support to repeal the excise tax translates into congressional passage as well as an expected presidential veto remains to be seen.

In the Senate, “we don't have the numbers yet” to override a veto, Mr. Klein said.

“The trick is to somehow find a way to disentangle the excise tax provision” from even more controversial provisions, such as eliminating the employer mandate, said Frank McArdle, an independent benefits consultant in Bethesda, Maryland.

“We are hoping the president would sign an excise tax repeal bill,” said Annette Guarisco Fildes, president and CEO of The ERISA Industry Committee in Washington. Whether that signature will happen — assuming lawmakers pass a repeal measure — largely “depends on what else is in the bill,” Ms. Fildes added.

Still, relief from the excise tax could come in other ways.

For example, lawmakers or regulators could make clear that the excise tax trigger should be adjusted to reflect widespread geographic differences in health costs and, with that, group health plan premiums.

“The tax is not fair. It depends much more on where a company and its employees are located than on the benefits provided” said Russ Blakely, a managing member of insurance broker Russ Blakely & Associates L.L.C. in Chattanooga, Tennessee.

Lawmakers or regulators also could clarify that employee contributions to health savings and flexible spending accounts are not included in calculating plan costs.

In addition, the number of employer plans hit by the tax would be reduced if regulators made clear that the tax applied only to medical benefits, and not ancillary benefits, such as dental and vision care.

“That would provide material relief,” said Randy Abbott, a senior consultant at Towers Watson & Co. in Boston.