Nearly all of Oregon's Congressional delegation has sent a letter asking federal officials to investigate whether a California wine producer is falsely labeling wines as an Oregon coast pinot noir.

The letter signed by both of Oregon's U.S. senators and four of its five U.S. representatives asks the Alcohol and Tobacco Tax and Trade Bureau to investigate.

The controversy is centered on the branding of a Napa Valley winery that buys Oregon grapes to use in its own pinot noir and rosé wines, the Capital Press reported Friday.

Joe Wagner, who owns and operates Copper Cane LLC, of Rutherford, California, called the controversy a "charade." He said he has been working with state and federal investigators.

But Oregon wine producers say the state's $5.6 billion wine industry needs to be protected from false claims.

Related: Oregon winegrowers fight to unravel California winery's tangled web of labels

Oregon officials say the state has 769 wineries and 1,114 vineyards that support 30,000 jobs.

-- The Associated Press