SAN DIEGO, Ca. - California regulators denied a Department of Homeland Security request to fortify the westernmost stretch of the U.S.-Mexico border, setting the stage for a possible legal battle between the state and the Bush administration.

The California Coastal Commission on Wednesday found that the harm the project would cause to sensitive habitats outweighed security benefits provided by filling in canyons and erecting additional fences along the final 3½ miles of the border before it meets the ocean.

"The operation might succeed, but the patient might die," Commissioner John S. Woolley said.

Much of the environmental concern stems from the Border Patrol’s plans to fill a deep, half-mile long canyon known as "Smuggler’s Gulch," with 2.1 million cubic yards of dirt, enough to fill 300,000 dump trucks.