In June of 2018, two Monterey County site inspectors visited a Salinas cannabis farm, where they encountered a small group of farmworkers who they suspected had been trafficked.

The farmworkers, who spoke no English, took off running when Monterey County Resource Management Agency officials approached them. They couldn’t go far, though — the cultivation site was fenced in. The farmworkers seemed terrified, the county’s prosecuting attorney later said.

Their behavior was unusual enough that inspectors called the Monterey County Sheriff’s Office, who sent deputies to investigate.

It soon became clear the dozen or so Hmong farmworkers, employed by labor contractor Levi Trimmigration, were living in substandard housing: metal shipping containers furnished only with camping equipment. They had no running water, no ventilation and slept on camping cots.

According to the National Human Trafficking Hotline, California is one of the most prominent sites of human trafficking in the U.S. In 2018, of the nearly 11,000 cases reported nationally, more than 1,600 came from California. About 150 of those cases were reports of labor trafficking.

A recent U.S. Supreme Court decision on private property rights has human trafficking experts, including former law enforcement officers, advocates, and attorneys, worried that trafficked laborers will now be left without anyone looking out for them. These advocates say union organizers are among the first to recognize signs of labor trafficking.

In the Cedar Point Nursery v Hassid decision, announced in late June, the Supreme Court decided to uphold private property rights over organizing rights, prohibiting California union organizers from fields and bunkhouses.

The conservative majority held that the access regulations allowed “physical invasion” of the land without compensation.

Increasingly, many farmworkers are indigenous Mexicans. In many cases, they do not speak, read, or write English or Spanish, and may be unaware of their rights while working in the U.S. That makes them vulnerable to labor abuses or trafficking.

“A lot of these workers are living in labor camps owned by the employer, are transported to and from their worksites, and these folks are isolated,” said Elizabeth Strater, United Farm Workers Director of Strategic Campaigns. “They never leave their employers’ property. In some instances, they are isolated by design.”