Environmental officials in Nebraska have released their preliminary review of a plan to modify the route of the controversial Keystone XL oil pipeline, concluding that the changes would allow the pipeline to avoid sensitive topography and would ease concerns about potential groundwater contamination.

Keystone XL would carry oil from Alberta's tar sands and the Bakken Shale of North Dakota and Montana to U.S. refineries.

In its draft evaluation, the Nebraska Department of Environmental Quality says that the rerouted pipeline would avoid the state's sensitive Sand Hills region, although it would still traverse sensitive soils. The agency also evaluated the possibility of spills from the pipeline, including 57 "special conditions" that TransCanada agreed to impose on the construction and operation of the pipeline to address potential incidents.

Activists who have been fighting the proposed pipeline are still reviewing the full evaluation from NDEQ, but some concerns jumped out in an initial review.

"They seem to largely be parroting the misinformation that TransCanada typically gives landowners," said Jane Kleeb of the nonprofit Bold Nebraska, which has organized local residents against the pipeline.

TransCanada welcomed the review as an "important step" toward the state and federal approvals the company needs before it can begin construction on the northern leg of the pipeline. Construction on the southern portion of the pipeline, which will run from Oklahoma to Texas, already has begun.

"This report shows the care and attention TransCanada has taken to reduce the pipeline's environmental impact, demonstrate that water sources are being protected, further enhance the pipeline's safety and to provide an independent public liaison officer," said Shawn Howard, a TransCanada spokesman.

Activists are keeping up the fight to block the pipeline. Local landowners are challenging a pipeline siting law in state court, and activists are reviewing the report "with a fine-toothed comb" ahead of a public meeting scheduled for December.

Kleeb said the special spill-prevention conditions that TransCanada claims to be applying are merely reiterating steps that the company would already be required to take under state and federal regulations. She also questioned the definition of "Sand Hills" that the NDEQ evaluation relies on and the economic figures that the agency cites, arguing that most jobs created by the pipeline will go to construction workers from out of state.

Kleeb also said the report does not provide enough information on the specific chemical makeup of the different varieties of crude that could travel through the pipeline.

NDEQ said the special conditions would "result in more rigorous adherence to industry standards," would require specific timelines to respond to spills and would result in closer coordination between the company and regulators. NDEQ also estimated that the pipeline would create or support more than 2,700 jobs in the state.

The report also identifies several types of crude that TransCanada says the pipeline could carry. They include synthetic crude oil, which is refined bitumen from Alberta's oil sands; dilbit, which is created by blending bitumen with a diluent such as natural gas condensate; and conventional light crude oil from the Bakken Shale.

TransCanada would provide more detail on the particular product in the event of a spill and has agreed to carry $200 million in third-party liability insurance that could cover spill-related costs.

The draft evaluation will be subject to public review and a Dec. 4 meeting before the state agency finalizes its report to Nebraska Gov. Dave Heineman (R). The governor's recommendation will go to the State Department, which is conducting a broader environmental review to determine whether TransCanada will receive the presidential permit it needs to build the pipeline across the U.S.-Canada border.

"This isn't a recommendation at this point; this is a draft evaluation that is presenting our findings to date," said Brian McManus, a spokesman for NDEQ.