Updated

Some environmentalists are objecting to an exhibit focused partially on the energy industry of Alberta, Canada, in the Smithsonian Institution's upcoming Folklife Festival on the National Mall.

The most eye-catching piece of the exhibit will be an 18-foot-tall off-road dump truck with 10-foot-high tires. It is a smaller version of trucks used to mine oil from tar sands in the province and is being used to draw attention to Alberta's growing importance as an energy supplier.

In a letter to the Smithsonian to be released Thursday, the Natural Resources Defense Council accuses the Alberta government of using its sponsorship of the exhibit to promote business in the Folklife Festival and ignore the ecological damage of oil mining and its contribution to global warming.

"The Folklife Festival on our National Mall has never been a crass trade show or business expo, and it should not become one now," said Susan Casey Lefkowitz, the organization's director of Canada projects. "If the show must go on, the public deserves to learn the full story about tar sands."

Alberta culture is one component of the festival beginning June 30, along with Native American basketry and the Latin music of Chicago. The energy business is one of 16 aspects of life of life in the western Canadian province to be depicted in the outdoor exhibit.

The province holds one of the largest petroleum deposits outside Saudi Arabia. The oil comes from tar sands that lie beneath forests, wetlands and lakes that are home to many species of wildlife.

The (Toronto) Globe and Mail first reported on the dispute and noted that Alberta has arranged sponsorships from oil companies including EnCana, Suncor, Conoco Phillips and Petro-Canada.

"Because Alberta is known for its resource base, it's entirely appropriate that we reflect on how people work," Murray Smith, the Alberta government's representative in Washington, told the newspaper.

Smithsonian officials said no money is coming directly from the oil companies.

"This is not an industry-sponsored exhibition," said Nancy Groce, curator of the Alberta section. "It would be disingenuous to do Alberta and not talk about energy business."

Festival Director Diana Parker said the Smithsonian worked with Albertan scholars, government officials and citizens to create an exhibit that would reflect a mix of traditional culture and contemporary life.

"We are not handing out materials for any side," Parker said. "The festival is not taking a position."

About 150 Albertans will participate in the festival, including Royal Canadian Mounted Police, dancers and ice sportsmen.

As for the huge truck that will be parked on the National Mall, it wouldn't be the first vehicle. The festival has often included signature vehicles, including a New York subway car and a painted bus from Pakistan.