The Associated Press

PIERRE - A contractor for a Canadian company planning to build a crude-oil pipeline in eastern South Dakota says professional estimates show that a leak is unlikely to occur more than once in 41 years.

Heidi Tillquist, of ENSD in Fort Collins, Colo., also said any such leak along the proposed 1,800-mile TransCanada Keystone Pipeline likely would be "very small."

The comments were made in written testimony for a December hearing by the state Public Utilities Commission on a request for a pipeline permit.

Pipeline opponents predict leaks will occur.

"If my line leaks, it's unfortunate, but it means somebody's field gets wet," said Curt Hohn, manager of WEB Water in Aberdeen. "If a crude-oil pipe leaks, that's a different problem entirely."

Also, many opponents oppose the chosen route for the pipeline, which would slice a 220-mile path through South Dakota on its way to an Illinois refinery.

Tillquist compared spill estimates to car insurance. "For example, your insurance agent might state that you are likely to have 1.5 crashes in 10 years. That does not mean that you will crash during that 10-year period."

She said the average size of a spill reported since federal Pipeline and Hazardous Materials Safety Administration standards took effect in 2002 has been 12 barrels.

Submitted testimony for TransCanada from Michael Koski, a consultant for a Tallahassee, Fla., company, addressed the question of why the pipeline was not planning to run alongside Interstate 29. The line wouldn't be allowed within the corridor "due to safety issues and the impediment the facility would create to highway maintenance and expansion," he said.

Interstate interchanges and overpasses would force the oil pipeline to veer from the route often, increasing the pipeline's "length and impact" and probably making it cost more, Koski said.