The images of South Dakota grassland blemished by 210,000 gallons of leaked Canadian crude oil could not have come at a worse time for the Keystone Pipeline’s operator, TransCanada, which on Monday will ask regulators in Nebraska to approve a different pipeline despite fierce opposition.

This week’s leak was grimly familiar for Bob Banderet, a rancher on the Keystone route in North Dakota, about 20 miles north of the spill. In 2011, Mr. Banderet said he had spotted “a geyser of oil shooting straight up in the air” from a Keystone pumping station near his property. He found the response by TransCanada to be flat-footed and opaque.

“As far as transparency, in my eyes they get a failing grade,” Mr. Banderet said.

Though TransCanada has spilled far less than many of its competitors, the Keystone Pipeline has sprung several leaks since it was began operating in 2010. The federal government fined the company $135,400 this year for safety violations including corrosion control, and since 2011, regulators have opened 13 enforcement cases against TransCanada.

Thursday’s spill follows the 2011 leak spotted by Mr. Banderet in North Dakota and a 2016 spill in South Dakota, each of which released more than 16,000 gallons. TransCanada has also reported several smaller spills.