A rare snail living in the foothills of the San Gabriel Valley is holding up a multimillion-dollar housing project in Bradbury and has been submitted for protection under the Endangered Species Act.

The San Gabriel chestnut snail was found by a biologist with the California Department of Fish and Wildlife last year at the site of the Oak View Estates project, only the third time the species was observed in modern times, according to the state agency.

On Monday, the Center for Biological Diversity filed a request to the office of the Secretary of Interior asking the U.S. Fish and Wildlife Service to begin a 90-day process exploring whether scientific evidence — including the state agency’s findings — warrants federal protection for the local mollusk. The nonprofit also asked the U.S. Forest Service to consider the snail a sensitive species.

The snail once inhabited areas of Compton and the Dominguez Hills in the 1930s before being wiped out by urban development. Today, it survives under cactus leaves or in damp soil along the foothills between Altadena and Glendora but mostly within the Angeles National Forest and San Gabriel Mountains National Monument, said Tierra Curry, biologist with the Center for Biological Diversity.

“Some people would think I am crazy for trying to save a snail,” Curry said during an interview, adding the San Gabriel snail recycles the soil by eating decaying vegetation and bacteria and dispersing seeds. The snail’s shell also acts as a source of calcium for birds. “These amazing little animals play critical roles in the environment and deserve to be protected like other imperiled wildlife.”

The 197-acre project proposed five estate homes that would directly impact 49 acres with grading, slope benches, debris basins, water and sewer infrastructure and filling in a stream within Bliss Canyon, according to the state agency’s assessment cited in the petition. The agency sent a letter to the city saying the project would directly impact the snail with no form of mitigation possible. It recommended preserving the land.

Bradbury planner Jim Kasama said the applicant realized its original design was “infeasible” due to the presence of the snail and many other environmental concerns. Kasama said the project is being redesigned to avoid environmental impacts. “We have not heard from Fish and Wildlife on this new design,” he said.

Jonathan Evans, senior attorney with the Center for Biological Diversity, said in an interview Monday he was not aware of a redesigned project. A spokesperson for the project could not be reached. Kasama said the applicant has not submitted plans and that the project is still in the very early planning stages.

The snail has a glossy, deep-brown spiral shell that is chestnut in color, hence the name, and is about 1 inch wide. It was found in Bradbury and Monrovia, the state agency reported.

The Los Angeles County Natural History Museum’s citizen-science project — called SLIME for Snails and slugs Living in Metropolitan Environments — has found empty shells or live specimens in the following locations: Eaton Canyon in east Pasadena; Fish Canyon Falls Trail near Duarte; the trail to Sturtevant Falls and Mount Wilson, both in the Chantry Flat area of the Angeles; Monrovia Canyon Park and Sierra Madre South Hills Park.

Protecting the snail would also mean preserving hillsides at the base of the mountains, allowing more room for other species to find food and reproduce, Evans said. “This is a species low down on food chain, but it’s all about habitat protected, which in turn can allow for greater habitat for deer, bear or wildcats.”

Curry said a decision from the U.S. Fish and Wildlife may take years and that a status review may take one year.