On Thursday, staff told the California Coastal Commission that approving such a project would set a precedent and invite other large developments to rugged, environmentally sensitive locations. Commissioners voted 8-to-4 against the proposal.

“In my 38 years I have never seen a project as environmentally devastating as this one,” said Peter Douglas, executive director for the commission. “An environmentally sensitive person would never pick this site to develop.”

Following the vote Fiona Hutton, spokeswoman for the property owners, said they would be “vigorously exploring all potential options including litigation.”

“The property owners worked diligently to develop home designs that would meet some of the highest standards for sustainability, blend seamlessly with the natural landscape and preserve the vast majority of their private lands as open space,” she said.

The proposal led by the musician, whose real name is David Evans, called for five multilevel homes of up to 12,785 square feet to be built on 156 acres in the Santa Monica Mountains. Project designers said the homes would have the top green building certifications and the guitarist said the mansions would be some of the most environmentally sensitive in the world.

Project opponents, including the National Park Service, however, said the development would scar the expansive ridgeline. The musician and his partners had earlier appeased one of its staunchest opponents, the Santa Monica Mountains Conservancy, after agreeing to give the agency more than $1 million, dedicate nearly 100 acres to open space and provide public access to hiking trails if the homes were approved.

One sticking point was the claim by proponents that they are five separate owners each building a single home on separate lots, an argument that would make it more difficult for the commission to deny their proposals.

Commission staff said the current owners did not adequately show that the properties were individually owned. Staff members said they believe the project is a single coordinated development with a single project manager, single architect, single website and – until recently – a single agent that came before the commission. Staff suggested building fewer homes on the site but proponents called that a violation of property rights.

To prove that each lot was under individual control, one owner flew in from England while others sent video clips telling commissioners they were not taking any direction from Evans regarding the development of their site. Attorneys, meanwhile, said commission staff’s single ownership theory would not stand up in court and that the owners are the entities that hold the titles.

Don Schmitz, the project’s planning consultant, told commissioners there are homes at similar elevations in the Santa Monica Mountains and there is plenty of development near the site including Malibu’s exclusive Serra Retreat neighborhood.

“We’re flummoxed to understand why we’re so special,” said Schmitz, adding that they’ve done everything that staff has asked. “There is nothing these property owners can do that they haven’t already done.”

In the end, however, most of the commission didn’t appear to buy that argument. While some complimented the project’s green intentions and overall design, which included organic features such as a home that wrapped around an existing pile of boulders, commissioners said the project was simply too big and sited in the wrong area.

Commission Chair Mary Shallenberger recalled talking with the musician and how “he and his wife fell in love with the land but couldn’t afford it so they got some friends to go in on it.”

“Yes they have a right to a house but they don’t have the right to the houses they’ve proposed,” she said. “People don’t have a right to build on the ridge just because it happens to be the most beautiful part on the property to build.”