DEL MAR – After a marathon 12-hour meeting, the state Coastal Commission late Wednesday night crippled a plan to extend a toll road from Orange County through San Onofre State Beach.

Commissioners voted 8-2 against the project, finding it was inconsistent with the state law regulating development along the coastline. The vote dealt a serious blow to the project's chances of obtaining a coastal development permit, a necessity before construction can begin.

The vote came about 11:20 p.m. and was greeted by cheering from several hundred people.

Pat Kruer of Rancho Santa Fe, the agency's chairman, voted against extending the road. The other commissioner from San Diego County, San Diego City Councilman Ben Hueso, was sick and did not attend the hearing.

In the end, the majority of commissioners agreed with the agency's staff, which concluded the $875 million four-lane road should be rejected because it would destroy natural habitats, wetlands and access to public recreation areas.

“How can we as the California Coastal Commission put a private road through a state park?” said commissioner Larry Clark, who serves as a councilman in Rancho Palos Verdes. “There are reasonable alternatives, from a transportation standpoint, that have not been explored.”

Commissioners who supported the road extension said they did not believe it would harm the park.

“After listening to hours of testimony from both sides, there is merit on both sides,” said William Burke, a commissioner from Los Angeles. “I'm not convinced (the park) is in jeopardy.”

The 16-mile extension of the state Route 241 toll road would link Rancho Santa Margarita and San Onofre. It would cut into the eastern portion of the popular San Onofre State Beach and end near Trestles, a famous surfing spot.

The Irvine-based Transportation Corridor Agencies, the state-established joint powers authority overseeing the tollway project, said the road would not touch the sand on the beach and would be hundreds of yards from San Mateo campground, part of the 3,000-acre state beach.

The hearing on the toll road started about 11 a.m. in Wyland Hall at the Del Mar Fairgrounds with a standing-room-only crowd estimated at nearly 3,000 at its peak. The commission took testimony from the project's developer, the agency's staff, elected officials and the public.

Proponents, many of them elected officials from Orange County, argued the road was needed to alleviate increasing traffic on Interstate 5 in both North County and south Orange County. It has been proposed for more than a decade.

Supporters said improving traffic flow would help the environment by reducing air pollution and helping drivers burn less gas. It would also save hundreds of homeowners and businesses from losing their property along Interstate 5 if that freeway is expanded and allow greater access to the coastline for those who live in the growing inland communities.

When the public was allowed to speak after 7 p.m., nearly 200 people registered their opposition to the project, while about two dozen voiced support.

Noemi Mora of Escondido cited safety as the key factor for building the road. She was stuck on Interstate 15 as she evacuated to Orange County during the October wildfires that destroyed her home.

“The existing roadways proved to be inefficient in an emergency. We were trapped,” Mora told the commission late Wednesday night.

Some of the most vocal opponents were surfers, who argued the road would block the sediment deposits that create the waves at Trestles. One group submitted to the commission 10 surfboards that had letters and signatures taped to them from people urging commissioners to reject the project.

They were joined by environmentalists, who said the road would destroy sensitive habitat for threatened or endangered species and increase water pollution at the state beach. Others just felt it was wrong to run a freeway through a state park.

“No one has proven there is a need for the toll road. Please accept your staff's recommendation,” said Mike Bullock of Oceanside.

Earlier in the hearing, the commission's staff set the tone by noting the importance of the project.

“This is the most significant project to come before this commission since the San Onofre nuclear power plant in 1974,” said Peter Douglas, the commission's executive director. “I know of no other coastal development project so demonstrably inconsistent with the law that has come this far in the regulatory review process.”

Throughout the hearing, opponents waved posters and fliers with messages expressing their opposition whenever someone urged the commission to reject the project.

Even before the hearing started, backers and opponents shouted at each other.

As hundreds of union workers entered the hearing wearing bright orange T-shirts with banners supporting the road, several hundred supporters joined them in chanting “Yes! Yes! Yes!”

Opponents wearing blue T-shirts that read “Save the Park, Stop the Toll Road” booed and shouted back “No! No! No!” and “save Trestles!”

“We need the work!” the union workers yelled.