Los Angeles County would become the epicenter for the financial hit, says the head of the L.A. World Trade Center, Stephen Cheung.
"Our largest trading partner is China. There is $150 billion of trade with China and Los Angeles every year," said Cheung.
A trade war promises punishing price hikes on goods the U.S. buys from China and vice versa. From aerospace parts to California produce, China's levies on local goods could make them so pricey China's consumers won't buy them.
And its not just local manufacturers that would be impacted. There is also the labor force that ships, trucks and distributes goods going both directions.
"This would directly affect our truck drivers, our logistics services and even retail," said Cheung.
China could also hammer U.S. companies operating within its borders. Cheung says there are 10,000 Chinese companies based in L.A. County including electric bus manufacturer BYD in Lancaster. Together, they are major employers providing 430,000 jobs locally.
"We don't want them to feel attacked," said Cheung.
More than 800 U.S. exports will be subject to tariffs starting July 6. Cheung says what is giving businesses a stomachache is that they don't know if President Trump is bluffing or not.
Cheung is urging everyone from producers, labor and consumers to lobby legislators and urge the president to take his finger off the tariff trigger. So much, he says, is at stake.
"If there is one region that stands to lose on this trade deal, it is us," said Cheung.