A new environmental review of TransCanada Corp.'s (TRP) controversial Keystone XL pipeline expansion has reaffirmed an earlier report that the pipeline meets environmental safety standards.

The 320-page supplemental draft environmental impact statement appears to be a victory for the pipeline expansion, which would take up to 1.1 million barrels a day of crude oil from Canada 1,900 miles to refineries on the U.S. Gulf Coast.

The supplemental environmental review was ordered in March after environmental groups and land owners in the path of the project raised objections about the possibility of oil spills and the environmental record of Canada's oil sands industry. Since the proposed pipeline project crosses state lines, the U.S. State Department must approve the project before construction begins.

While adding more environmental information about the potential for spills and the effect on climate change, the supplemental review said "no new issues of substance" had emerged from the public comments on the project, and that the additional review "does not alter the conclusions reached" in the previous report.

The previous report had concluded that the project would result in "limited adverse environmental impacts" and that the pipeline system "meets or exceeds industry standards and regulatory requirements."

A TransCanada spokesman said the company needed time to review the report before commenting.

Environmental groups said they were disappointed with the conclusions of the additional review.

"On first reading, we are concerned that the State Department has still not done a serious and thorough analysis of significant dangers, including the safety of tar sands oil pipelines and the pollution caused by tar sands oil production," the environmental group Friends of the Earth said in a release.

The public will have 45 days to comment on the supplemental draft. A final environmental assessment, as well as the State Department's final decision on the pipeline, is expected by the end of the year.

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