Cargo-handling equipment at the L.A. and Long Beach ports might soon be required to be zero emission under a new proposal, but terminal operators are concerned the necessary technology doesn’t yet exist.

The Zero Emissions Program, which is part of a draft discussion document for updates to the port’s Clean Air Action Plan, would require all cargo-handling equipment, including cranes and tractors, be zero emission by 2030.

The clean air program, known as CAAP, started in 2006 and is a road map the ports have used in addressing pollution in the San Pedro Bay. A separate CAAP program addresses truck emissions.

“The earlier two CAAP rollouts had tangible and shorter-term goals that were doable,” said Thomas Jelenic, vice president of Pacific Merchant Shipping Association, a trade organization that represents terminal and vessel owners. “Much of what is included in this draft is speculative and based on no known technology.”

Jelenic also said the time line is too aggressive: 2030 is too soon to be experimenting with technologies that might or might not work.

A study commissioned by the shipping association in 2015 put the additional capital costs, including equipment and electrical infrastructure, of moving to automated zero-emission technologies by 2030 at $18 billion for terminal operators and other companies involved in cargo movement. The study suggests the transition could cost billions of dollars more in added operating costs such as labor, maintenance, and energy.

The ports have disputed the study, saying the cost would be much less.

Heather Tomley, director of environmental planning at the Port of Long Beach, said the ports are reviewing the shipping and logistics industries’ concerns.

“We did put in an aggressive schedule for cargo-handling equipment to be zero emissions by 2030,” she said. “We’re evaluating the suggestions that came up and are looking into the technology, infrastructure, and economic aspects for the Zero Emissions Program.”

The Long Beach port last month received initial approval for a $9.7 million grant from the California Energy Commission to help fund a $13.7 million demonstration project to test new zero-emissions cargo-handling equipment for 12 months, officials said. The project includes designing and creating 25 new or converted electric cargo-handling vehicles.

An updated draft of CAAP is expected within the next two months. It will then be open for another round of discussion with a final draft going to both ports’ harbor commissions by late fall.