Oct 15 (Reuters) - The U.S. Supreme Court on Tuesday

declined to wade into claims being made by a growing number of

businesses that the National Labor Relations Board's in-house

enforcement proceedings are unconstitutional.

Justice Brett Kavanaugh denied an emergency application by

auto parts maker Yapp USA Automotive Systems to block an NLRB

case against it pending the outcome of its lawsuit claiming

board officials are improperly shielded from at-will removal by

the president.

Yapp in the underlying board case is accused of illegally

interfering with a union election at a Michigan factory, which

it has denied.

Kavanaugh, who oversees requests arising from Michigan and

other states covered by the Cincinnati-based 6th U.S. Circuit

Court of Appeals, did not explain his decision.

Lawyers for Yapp and an NLRB spokeswoman did not immediately

respond to requests for comment.

A federal judge in Michigan last month refused to block the

NLRB case against Yapp from proceeding, ruling that the company

was unlikely to prevail on its claims that the board's

administrative judges and its five members are illegally

insulated from being removed without cause.

Yapp says that because those officials wield executive

power, the U.S. Constitution requires that they be held

accountable to the president.

The company is appealing to the 6th Circuit, which on Sunday

denied its motion to stay the administrative case pending the

appeal.

Nearly 20 other companies including Amazon.com ( AMZN ), Elon Musk's

SpaceX and pipeline operator Energy Transfer ( ET ) have filed similar

lawsuits attacking the NLRB's structure and enforcement powers.

Three judges in Texas have temporarily blocked board cases from

moving forward, while at least four judges in other states have

refused to do so.

At a panel discussion on Tuesday hosted by the National

Press Club in Washington, D.C., NLRB General Counsel Jennifer

Abruzzo said the legal challenges by Yapp and other companies

were an attempt to distract from their violations of federal

labor law. But she said the board would not waver in protecting

workers' rights.

"Everybody in this country needs us," said Abruzzo, an

appointee of Democratic President Joe Biden. "It would be chaos

if the agency was not allowed to perform its functions and do it

properly."

The case is Yapp USA Automotive Systems v. NLRB, U.S.

Supreme Court, No. 24A348.

For Yapp: Timothy Garrett of Bass, Berry & Sims; Matthew

Nelson of Warner Norcross + Judd

For the NLRB: Michael Dale

Read more:

US Supreme Court asked to weigh in on challenge to NLRB's

structure

US judge rejects auto parts maker's challenge to NLRB

structure

Amazon ( AMZN ) challenges US labor board's structure in lawsuit over

union election

SpaceX wins block on US labor board case over severance

agreements

US judge blocks NLRB case against energy firm challenging

agency's structure

US judge rejects medical center's bid to 'neuter' NLRB

NLRB's Abruzzo hits back at 'low-road' companies challenging

agency's structure

(Reporting by Daniel Wiessner in Albany, New York)