A day after President Obama’s surprise comments on the Keystone XL pipeline, lawmakers and interest groups remain puzzled by what they heard.

Most said Obama’s comments were vague enough to leave advocates and foes of the pipeline scrambling to figure out how the administration will determine whether Keystone exacerbates carbon emissions.

Some say Obama’s remarks could allow him to delay the pipeline, which would bring carbon-heavy oil sands from Canada to the Gulf Coast.

“We view this somewhat with suspicion because this is another potential avenue to delay or potentially derail the pipeline,” said Matt Letourneau, a spokesman with the U.S. Chamber of Commerce’s Institute for 21st Century Energy.

Others said Obama’s comments give them hope approval is coming since the State Department in a draft environmental analysis already found Keystone would not substantially hike greenhouse gas emissions.