Lawrence Livermore National Laboratory (LLNL) marked Site 300's 70th anniversary in May with two events celebrating the Experimental Test Site's history, mission and people: an Employee Appreciation Day and a family-focused open house.
Although Site 300 reached its 70-year milestone last fall, celebrations were delayed due to a lapse in federal government funding. The rescheduled events gave employees, families and guests an opportunity to recognize seven decades of contributions to national security while highlighting the people, facilities, technical capabilities and environmental stewardship that continue to define Site 300 today.
Celebrating the people behind the mission
The Employee Appreciation Day program on Thursday, May 14, brought together Site 300 personnel, Laboratory leaders, National Nuclear Security Administration Livermore Field Office representatives and employees from across LLNL for an outdoor ceremony. The event included leadership remarks, anniversary memorabilia and a time capsule display to mark the milestone anniversary.
Brad Wallin, deputy director for Strategic Deterrence, reflected on Site 300's origins in 1955, when the Laboratory needed its own dedicated high-explosives testing facility to support rapid design iteration and experimental work.
"When the Lab started in 1952, we didn't have our own dedicated explosive testing facility," Wallin said. "We needed to do experiments at a rate and with a fidelity that we couldn't do by traveling teams back and forth to Los Alamos."
Wallin said Site 300 became foundational to early Laboratory design efforts, supporting hundreds of tests in its first years and contributing to key developments in the modern stockpile, including miniaturization and improved safety. Over time, the site's mission expanded to include insensitive high explosives, advanced diagnostics, hydrodynamic testing and other capabilities central to stockpile stewardship and modernization.
"Today, Site 300 is a key part of our national security infrastructure," Wallin said.
Tom Grim, deputy manager of the Livermore Field Office, thanked employees for their work and emphasized the growing demand for Site 300's capabilities, including high explosives, hydrodynamic testing and advanced diagnostics.
"Site 300 has done many amazing things and been very successful over the last 70 years," Grim said. "But the most important thing is the work in front of us right now and in the future."
Charles Slama, associate deputy director for SD Operations, thanked the planning team and volunteers who supported both anniversary events, noting that 66 planning team members and more than 200 volunteers helped organize and support the activities.
"Our Site 300 team members are part of our Livermore family," Slama said. "This event is not only to recognize Site 300, but to recognize you and really share our appreciation for you."
As part of the ceremony, employees viewed items that will be placed in a 2025 Site 300 time capsule, including program challenge coins and patches, an FXR target wheel, team photos, additive manufacturing test parts, a wax replica of a machined part and a Site 300 natural resources field guide featuring protected plant and animal species.
The event also featured materials recently recovered from an earlier time capsule buried in fall 1980 before construction of the Advanced Test Accelerator (ATA). After 45 years underground, the capsule's contents, including 1980 newspapers, coins, photographs, fossils and ATA information, were displayed for employees to view.
Wallin closed the program by emphasizing that Site 300's success has always depended on its workforce. "We've talked a lot about the incredible capabilities out here and the innovations that have happened throughout the years," Wallin said. "But the key to all of that is you."
Following the program, employees enjoyed lunch and took part in the Site 300 vehicle show hosted by LLESA, which featured classic cars, modern models, motorcycles and off-road vehicles.
Sharing Site 300's story with families and guests
The anniversary celebration continued Saturday, May 16, as Site 300 welcomed employees, families and guests for an open house highlighting the site's mission, history, capabilities and natural resources. The open house gave guests an opportunity to visit the 11-square-mile Experimental Test Site and learn more about the work performed across its seven functional areas.
A central feature was the Site 300 windshield tour, which offered visitors a guided look at the site's operations, Cold War history and Altamont Hills landscape. Tours operated regularly throughout the morning and included stops focused on natural resource protection and the Outdoor Firing Facility.
At the Outdoor Firing Facility stop, guests learned how explosives testing is conducted safely through careful preparation, sound forecasting and blast protection. From a safe distance, visitors saw the firing table, protective bunker and storage magazine. At the natural resource protection stop, guests met Lab wildlife biologists and learned about LLNL's natural resource protection and compliance program.
The open house also featured a program showcase with booths representing Site 300's functional and research areas, including the Outdoor Firing Facility, Contained Firing Facility, explosives storage and distribution, high explosives manufacturing, shock and vibration testing, materials aging and compatibility and the Facility for Advanced Manufacturing of Energetics (FAME).
Families participated in the Site 300 STEM Camp passport activity, where children earned sticker "badges" by completing hands-on activities at booths throughout the day. Activities included online coding games, computer component identification, a penny float engineering challenge, fusion science demonstrations and a paper airplane flight challenge.
Guests also viewed a historic weapons showcase featuring Fat Man, Little Boy, the W56 and the W47. Additional activities included LLNL merchandise, yard games, a complimentary light breakfast and live music.
From employee recognition and time capsule displays to family STEM activities and guided tours, the anniversary events reflected the breadth of Site 300's mission and the generations of employees who have helped make the site an enduring part of LLNL's national security enterprise.
