Democratic presidential candidate and former Vice President Joe Biden tours the Plymouth Area Renewable Energy Initiative in Plymouth, New Hampshire on Tuesday. (Brian Snyder/Reuters)

Joe Biden’s presidential campaign lifted language without credit, at times word for word, when crafting its education and climate plans, incidents the campaign acknowledged and said were inadvertent.

The incidents appeared to be staff errors when detailing Biden’s policies, and they underscored how hastily his campaign was attempting to put out specific proposals. But the issue was a particularly sensitive one for Biden, whose 1988 campaign was derailed after he plagiarized, in speeches, rhetoric used by British politician Neil Kinnock.

Reports also emerged that he used lines from two Democrats, Robert F. Kennedy and Hubert H. Humphrey, without attribution. Biden had also been cited for plagiarism in a paper during law school, an error he blamed on not knowing how to properly cite sources. He quit the campaign shortly after the flurry of uses was reported.

Biden’s campaign said Tuesday that it would update his policy plans online to properly attribute the sources of information, which in the case of his environmental plan included a coal industry entity. But the controversy nonetheless threatened to overshadow the policies themselves — and, for some liberal advocates, it was a sign that the policies were not taken seriously by the campaign or the candidate.

“Biden appears to be taking ideas from other people and not giving credit. You can’t do that,” said Leah Stokes, a political scientist at the University of California Santa Barbara who specializes in climate issues. “It speaks of pulling an all-nighter and reading off of your friend’s essay.”

Other campaigns have used unattributed language similar to that crafted by primary sources. A policy plan by Sen. Kamala D. Harris (D-Calif.) includes a line that “black women are three to four times more likely to die from ­pregnancy-related causes than white women.” That is identical to a reference in an American Heart Association document, which attributes the statistic to the Centers for Disease Control and Prevention. “It’s a statistic,” campaign spokesman Ian Sams said when asked for comment.

In the case of his education policy, Biden used a sentence word for word from an education policy publication from the group XQ Institute.

“Students who participate in high-quality career and technical education are more likely to graduate, earn industry credentials, enroll in college, and have higher rates of employment and higher earnings,” the sentence read.

The institute did not immediately respond to requests for comment, and the Biden campaign declined a request for comment on the education policy passage. After The Washington Post contacted the campaign about the sentence, it added a link to the institute’s publication.

The use of other groups’ words in Biden’s environmental plan became known after Josh Nelson of the progressive group CREDO noticed Tuesday that much of its language about carbon capture sequestration appeared to resemble talking points from pro-industry groups.

Nelson found the phrases were a near-identical match with wording used by the Carbon Capture Coalition, whose members include Shell, Peabody Energy and Arch Coal.

Biden’s climate plan calls for making carbon capture, use and storage a “widely available, cost-effective, and rapidly scalable solution to reduce carbon emissions to meet mid-century climate goals.”

On its website, the Center for Climate and Energy Solutions’s Carbon Capture Coalition says “its goal is to make carbon capture, use and storage (CCUS) a widely available, cost-effective, and rapidly scalable solution to reduce carbon emissions to meet mid-century climate goals.”

“It is certainly not a good sign for a Democratic presidential candidate to be copying things verbatim from a group associated with the coal industry,” Nelson said.

Alec Gerlach, communications director for the Center for Climate and Energy Solutions, said it does not coordinate with campaigns. But he added “carbon capture should be an essential element in any comprehensive strategy to eliminate carbon emissions.”

At least one environmental group didn’t mind seeing its ideas influence White House hopefuls.

In its climate plan, for example, the Biden camp copied a factoid — the “average American sewage pipe is 33 years old, with many pipes dating back 50 or even 100 years” — verbatim from the website for American Rivers in a section about water infrastructure.

But Amy Kober, a spokeswoman for the American Rivers clean-water advocacy group, said her organization was “absolutely happy to see anybody come to our website.”

“Our information is available to all campaigns,” she added.