State Department officials could get an earful from critics in two states Monday over the agency's report concluding there are unlikely to be any serious environmental problems with a proposed oil pipeline stretching from Canada to the Texas coast.

The department kicks off this week's series of hearings on the Keystone XL pipeline with meetings Monday in Topeka, Kan., and Port Arthur, Texas. Officials may give a brief statement but don't plan to answer any questions, reserving most of the time for comments from the public _ including environmentalists who argue the pipeline would be a source of "dirty oil."

"We see these as listening sessions," said Kerri-Ann Jones, assistant secretary for the Bureau of Oceans and International Environmental and Scientific Affairs, a State Department agency. "We want to listen and hear what people have to say."

Other meetings have been scheduled this week in Montana, South Dakota, Oklahoma and Nebraska. Even in that deeply conservative state there is growing concern about the pipeline's effect on the Ogallala Aquifer, a vast subterranean reservoir that spans a large swath of the Great Plains and provides water to much of Nebraska and seven other states.

The State Department, which has to approve the 1,700-mile Keystone XL pipeline because it would cross the U.S.-Canada border, is expected to decide by the end of the year. The sessions are likely to focus on the department's final draft of its environmental impact statement on the pipeline, which found that special conditions put on the pipeline would result in a project with a "degree of safety greater than any typically constructed domestic oil pipeline system under current regulations."

The department said on its website that participants at the meetings are encouraged to talk about whether they think the pipeline is in the U.S. national interest. The department also says that its decision on Calgary-based TransCanada's application for the pipeline permit will take into account several factors, including "environmental, economic, energy security, foreign policy, and pipeline safety concerns."

The proposed $7 billion pipeline, which would move tar sands oil from Alberta, Canada, would hook up to TransCanada's existing pipelines and move oil to Oklahoma and the Gulf of Mexico.

Keystone XL has drawn criticism from some who say tar sands oil requires huge amounts of energy to extract and that a spill along the pipeline could cause an environmental disaster.

TransCanada and its supporters say the pipeline would mean tens of thousands of U.S. jobs and more energy security for the country.

"If the activists feel that they're facing an uphill battle, it's because the facts don't support their overheated rhetoric," TransCanada spokesman Shawn Howard said. "It has been shown that the outrageous claims these groups have made aren't true."