NORRIDGEWOCK, Maine — U.S. Trade Representative Ron Kirk toured the New Balance factory Thursday morning as Maine lawmakers expressed concern that tariffs protecting America’s footwear industry could be threatened by a free trade deal Kirk is negotiating.

New Balance President and CEO Rob DiMartini held up his company as an example of how businesses in the United States can compete in the global market. He said there was not a single job lost at his company during the recession.

After a tour of the factory, where he talked with workers and saw how the athletic shoes were made, Kirk spoke to a crowd of about 200 workers in an assembly area.

“You all have made me really proud of everything we’re doing to make sure we use our trade policy to protect jobs, to fight for jobs and to keep those jobs here,” said Kirk, President Barack Obama’s principal trade adviser.

U.S. Rep. Mike Michaud, D-Maine, and representatives of U.S. Sens. Susan Collins, R-Maine, and Olympia Snowe, R-Maine, were present, along with state Reps. Jeff McCabe, D-Skowhegan, and Sharon Anglin Treat, D-Hallowell.

Kirk said the United States is involved in talks with several nations regarding the Trans-Pacific Partnership, a free trade agreement being negotiated among countries in North America, Asia and Australia.

“The Trans-Pacific Partnership is the biggest opportunity we have in the near term to open up new markets for American goods … in one of the fastest-growing areas,” said Kirk. “We decided to join this a few years ago because we saw a great opportunity for us to find a new market to balance, frankly, the slowdown in our trans-Atlantic relationships.”

Michaud said he and Kirk have not seen eye to eye on trade issues. Repealing the tariffs on foreign-made footwear would hurt employees at New Balance, he said. Their differing views haven’t stopped them from discussions, however.

“He got to witness firsthand the great work being done by Maine’s highly skilled workers, and I know they really helped drive home the point that these tariffs must be preserved,” said Michaud.

Though not in attendance, Collins and Snowe also urged Kirk to consider the 900 jobs at New Balance plants in Maine that would be affected if the tariffs on imported shoes were lifted.

“I sincerely hope that he considers the potentially devastating impact a faulty and ill-informed Trans-Pacific Partnership agreement could have on our nation’s only remaining athletic shoe manufacturer,” Snowe said in a statement.

Collins relayed a similar message.

“I hope Ambassador Kirk leaves with a greater appreciation of the role this industry plays in Maine’s economy and will not pursue trade policies that could undermine it,” Collins said in a press release.

While talking with the workers, Kirk noted how many of them had been with New Balance for a long time — some for decades.

“America wants to work. And these are good jobs,” said Kirk. “When I talk with people and they say they’ve been here for 30 years, that’s all I need to know.”

Kirk emphasized that more manufacturing jobs are needed in the U.S.

“We need to make manufacturing sexy again in America,” said Kirk, eliciting laughs from the audience. “Everybody was going to be a dot-com millionaire and all of us that went to school and worked every day were chumps. Then the dot-com bubble [burst]. There’s nothing wrong with a good job that let’s you feed your family, put a roof over your head and send your kids to school. We need more jobs like that in America.”

Kirk gave little indication of how close the United States is to joining the Trans-Pacific Partnership. The U.S. is currently hosting the 14th round of negotiations in Leesburg, Va.

“These are horribly technical and detailed [negotiations],” said Kirk. “We are making progress, but I’ll be honest, we’ve mostly resolved the least difficult issues. How we treat textiles in general, like footwear, is going to be one of the more challenging issues.”

McCabe and Treat attended the negotiations in Virginia on Sunday.

“We have an uphill battle, but there is an opportunity to make sure that the shoe tariffs are among the 25 percent of trade goods that are protected,” said Treat.

“We are pleased that the U.S. trade representative is taking our concerns very seriously, especially after what we heard in Virginia,” said McCabe. “People in Skowhegan rely on these good-paying jobs. We take pride in the ‘Made in America’ label. Our neighbors had a hand in it.”

The United States isn’t afraid of global competition, said Kirk, but he wants a level playing field.

“China’s one of the biggest markets we’ve got, but they have to play by the rules just like we do,” he said. “Whether it’s China, Europe or anybody else, the one message we’ve got is: ‘We’ve opened our markets to you, but it’s time you do the same thing for us.’”

Kirk mostly kept the mood light as he joked about being a Dallas Cowboys fan in New England Patriots territory.

“I didn’t know which would be more dangerous — a trade guy coming to Maine or a Dallas Cowboys fan,” said Kirk. “I did find one Giants fan, and I ribbed him a little bit.”

Kirk, the former mayor of Dallas, was presented with a pair of New Balance sneakers that are orange to represent the color of the University of Texas, where he earned his law degree.

New Balance is headquartered in Boston and has three manufacturing plants in Maine — in Norridgewock, Skowhegan and Norway.