A plan to expand the Los Angeles Zoo moved forward on Wednesday after a unanimous vote by the Los Angeles City Council.

The 13-0 decision approves the environmental impact report for the planned expansion of animal enclosures, facilities and conservation efforts, the Los Angeles Times reported.

The environmental impact, however, is what has critics concerned about the project, for which “key details…remain unknown,” according to the Times.

Currently, the zoo’s proposal would develop 16 acres of hillside near the zoo in Griffith Park, something critics say would be deleterious to local wildlife.

“We really tried to persuade the zoo, persuade Council District 4, to keep working on not impacting all the habitat that is there,” Gerry Hans, president of Friends of Griffith Park, told the Times.

Supporters of the project, dubbed the Vision Plan, point out that many of the zoo’s facilities date to the 1960s. They’ve been working since 2016 on implementing the Vision Plan.

Supporters noted that the zoo has been receptive to feedback and changes proposed by the community, a sentiment echoed by Councilwoman Nithya Raman, whose 4th District contains the zoo.

“Given the zoo’s willingness to respond to community feedback, I feel confident that as they develop detailed project designs, that any additional concerns can and will be addressed,” she said in a statement. “My staff and I are committed to continuing to work with them, and elevating community concerns, as we have throughout the process so far.”