Many of the safety systems in place at a federal laboratory in New Mexico where key components of nuclear weapons are developed date to the late 1970s and will likely need to be upgraded to meet future demands, an official with an independent oversight panel said Wednesday.

Sean Sullivan, chairman of the Defense Nuclear Facilities Safety Board, made the comments at the start of an hours-long public hearing focused on the risks of plutonium work conducted at Los Alamos National Laboratory.

Los Alamos, the birthplace of the atomic bomb, restarted development last year of plutonium cores used to trigger the explosion in nuclear weapons. The U.S. Energy Department wants to ramp up production.

The plutonium facility has drawn the attention of the board and other oversight agencies for safety issues and problems with the aging building's seismic stability and fire system.

The board in a letter sent in January to Energy Department officials said there were significant questions remaining about the suitability of the facility for long-term operations. More concerns were raised in April after a fire inside the concrete building resulted in minor injuries.

On Wednesday, board staff members mentioned the failure of diesel pumps that are part of the fire suppression system.

"Many of the facility safety systems relied upon to protect the public are of original vintage. They do not employ modern technology and have been prone to failure," Sullivan said.

He acknowledged that personnel at the plutonium facility have identified deficiencies, but resolution of the issues depends on uncertain federal funding and have often been deferred.

Officials with the National Nuclear Security Administration told the panel that Los Alamos has made substantial upgrades in recent years, including structural changes to protect against a natural disaster such as an earthquake.

Major construction projects aimed at boosting the reliability and safety of plutonium operations at Los Alamos amount to an investment of about $3 billion, said James McConnell, NNSA associate administrator for safety, infrastructure, and operations.

Over the past four years, an additional $350 million has been spent on maintenance and smaller projects to improve safety and infrastructure. An additional $95 million will be spent in the coming year on the fire system, ventilation and other upgrades, officials said.

"The safety and security of the workforce, our facilities and the public remain our top priority," McConnell said.

Scrutiny of operations at Los Alamos intensified in 2014, when a container of waste left over from decades of bomb-making was inappropriately packed at the lab and shipped to the federal government's only underground nuclear waste repository, where it later ruptured.

The resulting radiation release at the Waste Isolation Pilot Plant in New Mexico forced its closure for nearly three years and disrupted the federal government's multibillion-dollar cleanup program. The incident led to policy and management overhauls and an expensive settlement with the state.