AMHERST, S.D. -- TransCanada Corp. says it has recovered more than 24,000 gallons of oil from the site of a pipeline leak discovered last week in South Dakota.

The company said 24,450 gallons of oil had been recovered as of Wednesday. TransCanada's Keystone pipeline leaked an estimated 210,000 gallons of oil on agricultural land in Marshall County, South Dakota.

The company says there are roughly 170 people on-site working on cleanup and remediation.

South Dakota officials don't believe the leak polluted any surface water bodies or drinking water systems.

A TransCanada spokeswoman said Tuesday the cause of the leak won't be known until further investigation.

The damaged pipe will be cut out and sent to the federal Pipeline and Hazardous Materials Safety Administration for analysis.