(Adds voting result, Occidental comment, prior vote totals, details on BlackRock stake and influence)
By Ross Kerber
BOSTON, May 12 (Reuters) - Asset manager BlackRock Inc on Friday said it voted in favor of a shareholder proposal calling on Occidental Petroleum to report on the impact climate change could have on the energy company's business, helping it to pass.
The comments by BlackRock, the world's largest asset manager, also marked a more detailed level of explanation than it has traditionally offered for its proxy votes, which could make it even more influential.
BlackRock, a major Occidental investor, last year had opposed a similar shareholder resolution, which failed to get a majority of support from investors.
In a statement sent by a BlackRock spokesman explaining the switch, the fund firm said that despite talks with Occidental, "we remain concerned about the lack of discernable improvements to the company's reporting practices" on climate issues.
An Occidental spokesman said via e-mail the shareholder resolution passed at the company's annual meeting, held in Houston, Texas on Friday.
"The board acknowledges the shareholders' support for this proposal," Occidental Chairman Eugene Batchelder said in a statement e-mailed by a company spokesman. "We look forward to continuing our shareholder engagement on the topic and providing additional disclosure about the Company's assessment and management of climate-related risks and opportunities."
Last year a similar resolution was narrowly defeated with 249 million votes cast "for" it and 259 million votes cast "against."
BlackRock was listed as Occidental's largest investor with about 8 percent of shares in the company's latest proxy statement, suggesting its switch helped give the proposal a majority of support this year.
BlackRock had said in March it planned to put new pressure on company boards on issues including climate change and boardroom diversity. (Reporting by Ross Kerber; Editing by Meredith Mazzilli)