However, a condition of the funding is that the new equipment must be operated by human workers.

These drivers of the electric tractors will work alongside over 100 automated vehicles and 70 driverless container-stacking cranes at the highly automated port terminal, aiming to achieve emission-free operations by 2030.

The US transportation sector is a significant contributor to greenhouse gas emissions, as highlighted by the US Environmental Protection Agency (EPA).

In the race to replace diesel-powered equipment with cleaner electric alternatives, seaports are also exploring automation technology to enhance cargo processing capabilities.

Union leaders perceive increased automation as a threat to job security, and they have found support in the White House.

While the $30 million grant constitutes only a fraction of the total cost of the terminal's $2.5 billion modernization programme, unions and their supporters hope that grants like this will demonstrate the importance of prioritizing jobs as American employers adopt green technologies.

During west coast port labour negotiations, the unions representing seaport workers chose not to comment directly.

However, the AFL-CIO's Transportation Trades Department, which includes members from the railroad and airline industries, made it clear that unions are focused on safeguarding jobs.

"We've been dealing with technological change for 100 years in terms of transportation labour," said department president Greg Regan.