The Pennsylvania Conference of Teamsters yanked its endorsement of Democratic congressional candidate Bryan Lentz.
The union broadcast the falling out in a news release Thursday saying that it "no longer finds that Bryan Lentz would be the best representative for its members in the Seventh Congressional district."
The group went one step further on its website, posting a crossed out picture of Lentz and the words, "Say No To Lentz" written in red.
Lentz's campaign manager, Kevin McTigue, would not elaborate on what caused the rift.
"Bryan Lentz's only focus is and has been putting people back to work, including Teamsters," he said. "Since Pat Meehan won't come out of hiding you have to wonder what he promised the Teamsters leadership to get them to go against their members interests."
Meehan spokeswoman Virginia Davis shot back.
"Working families, small businesses and now labor organizations are realizing that Bryan Lentz is the wrong candidate to create jobs and lead us in these difficult economic times," she said. "These folks know that Bryan Lentz has a record of saying one thing as a candidate and doing something completely different once safely in office."
The union typically endorses Democrats, and has thrown their support behind democrats Dan Onorato, a gubernatorial candidate, and U.S. Rep. Joe Sestak in his bid for Senate.
Sources say the tiff stems from a bill Lentz sponsored that cracks down on construction firms that misclassify workers to avoid paying taxes. Gov. Rendell signed the bill into law by last week.
Lentz, 46, a two-term state representative from Swarthmore, is running to replace Sestak in the Seventh Congressional District, which includes Delaware County and parts of Montgomery and Chester counties. He faces Republican Patrick Meehan, 54, a former U.S. Attorney from Drexel Hill, and Jim Schneller, 54, a third-party candidate from Wayne.
The Pennsylvania Conference of Teamsters represents 92,000 members across the state.