environmental justice center

Puente Hills Landfill Park (PHLP) will transform the former Puente Hills Landfill — once the nation’s second-largest — into Los Angeles County’s first new regional park in three decades and the home of its inaugural Environmental Justice Center. The project seeks to repair long-standing environmental impacts on nearby communities and model meaningful, community‑driven stewardship. Our multidisciplinary team is leading architectural and engineering efforts, including solid waste engineering, in close partnership with LA County Public Works, Parks & Recreation and the Sanitation Districts.

Phase One introduces the Hilda L. Solis Environmental Justice Center (EJC), a regenerative building set within a restored native landscape. Interactive exhibits and an active learning center communicate visitors’ value, welcoming all kinds — humans, wildlife, rescued raptors and native plants — to highlight the importance of ecological systems.

New public transit, a park shuttle, school bus and rideshare access, parking and multi‑use trails offer total inclusivity and accesibility. A central rotunda links to the exhibits, classrooms, makerspace, lecture hall, outdoor amphitheater, media studio and raptor enclosure. The EJC itself functions as a teaching tool, showcasing leading sustainable strategies, focusing on robust building methods and processes such as recycling, composting, and salvage. The design is on target to achieve LEED Gold, net‑zero energy (operational carbon), a 50%+ embodied‑carbon reduction and a 50% cut in potable water consumption. Since the landfill closed in 2013, the Sanitation Districts have maintained the site under a state‑approved closure plan, including a well-protected clay soil cap and methane‑to‑energy gas collection system that reduces greenhouse gas emission. All Phase One buildings sit on native soil but remain near buried waste, prompting HDR to design a multifaceted mitigation system with membrane barriers, passive venting and continuous monitoring to ensure occupant safety, protect sensitive infrastructure, safely plant new trees, and provide accessible routes and recreational areas.

The project is currently in construction with an expected completion date of March 2026. The next phase will introduce passive, nature‑focused recreation atop the settling landfill, which continues to shift one to five inches per year.