Since late June, federal authorities have seized $961 million worth of goods over suspected ties to forced labor, according to a report released April 17 by CNBC.

In many instances, companies have no idea their supply chain is tainted, officials said.

CNBC received exclusive access in February to the Port of New York and New Jersey, where millions of dollars’ worth of cargo — from solar panels to bedding to floor tiles — was being held while major companies scrambled to prove their supply chains are clean.

“Our goal for the forced labor laws [is] to prevent merchandise from being made with forced labor in the first place, and we will not rest until we achieve that goal,” said Customs and Border Protection (CBP) executive assistant commissioner AnnMarie Highsmith, who oversees the Office of Trade.

According to Highsmith, enforcing the Uyghur Forced Labor Prevention Act, or UFLPA, signed into law by President Joe Biden in late 2021, is a top priority for CBP and the department. “This is not just a supply chain security issue for us,” Highsmith said. “It is an economic security issue for the country.”

Highsmith told CNBC that Chinese has taken steps to obfuscate supply chains and prevent businesses from learning [about] the conditions under which products are manufactured.

Her message to American businesses: “know your supply chain.”

But it isn’t that easy.

Surprisingly, the most recent CBP data shows that in terms of value, the majority of shipments detained since last summer were not sent from China. Shipments coming directly from China represented about $80 million worth of goods, while Malaysia accounted for $461 million and Vietnam accounted for $370 million. CBP officials told CNBC those shipments were stopped because the goods were believed to have been made with raw materials from the Uyghur region.

To date, only about a third of those detained shipments, amounting to 1,090, have been released.