Forced Labor Enforcement Just Crossed A Border: What CBP’s Serbia Copper WRO Means For Your Supply Chain

Key Takeaways 

• CBP continues to chase the company, not just the country. Zijin’s parent was already on the UFLPA Entity List for forced labor in China; this Withhold Release Order (WRO) hits its Serbian copper operation on a separate evidentiary basis. Moving production to a “friendly” country does not move you out of CBP’s reach. 
• Copper just joined the enforcement map. Forced-labor detentions are no longer concentrated in apparel, solar, and cotton. If you import copper—or anything containing it—your supply chain is now in scope, and most copper-reliant importers have done zero forced-labor due diligence. 
• The burden is on you, and it lands the moment your shipment is detained. Under a WRO, there is no notice and no grace period. You either prove your goods are clean by detailed documentary evidence, or you export or destroy them. 

On June 16, 2026, U.S. Customs and Border Protection (CBP) issued a Withhold Release Order against copper and copper products manufactured in Serbia by Serbia Zijin Copper D.O.O.—the fourth WRO of Fiscal Year 2026 and the second targeting a Serbian operation in roughly six months. Effective immediately, CBP personnel at every U.S. port of entry will detain shipments of copper and copper products from this company. 

If you read that as another distant enforcement headline, you are missing the part that should concern you. This action marks a clear shift in how forced-labor enforcement operates—and it removes one of the most common assumptions importers have used to manage their risk. 

The Real Story: Enforcement Follows the Entity Across Borders 

The instinct after the UFLPA took effect was straightforward: move sourcing out of China, and reduce forced-labor exposure. Nearshoring and “friendshoring” became risk-management strategies as much as cost strategies. 

The Zijin action dismantles that logic. 

Zijin Mining—the parent company—was already added to the UFLPA Entity List in January 2025 over forced labor tied to its operations in China’s Xinjiang region. CBP has now reached its Serbian copper operation through a WRO, a separate forced-labor enforcement mechanism that can be applied to any product and any company in any country. The throughline is not the country. It is the company. 

CBP’s investigation drew on worker statements, photographs, focus-group field notes, text-message screenshots, open-source NGO reports, news media, and academic research. Taken together, that evidence established the existence of six International Labour Organization indicators of forced labor among workers at the Serbian facility: abuse of vulnerability, withholding of wages, intimidation and threats, restriction of movement, retention of identity documents, and excessive overtime. Independent reporting has documented migrant workers from China, India, Nepal, Zambia, and Indonesia at the site. 

The lesson for importers is direct: a country-of-origin change is not a forced-labor compliance strategy. If a producer in your supply chain—or its parent—has a forced-labor history anywhere in the world, relocating the factory does not eliminate the risk. CBP has demonstrated it will follow the entity. 

Copper Is Now on the Map—and Most Importers Aren’t Watching It 

UFLPA forced-labor enforcement focuses on specific sectors: cotton and apparel, polysilicon and solar, seafood, tomatoes. Importers in those industries learned, often painfully, to map their supply chains to the raw-material level. 

Copper importers, by and large, have not. 

Copper is a base input across construction, electrical, and electronics manufacturing, electric vehicles, renewable energy infrastructure, plumbing, and HVAC. That means the population of businesses now exposed to forced-labor detention is far broader than the population that has prepared for it. If your bill of materials includes copper wire, copper tubing, copper bars, or finished goods that incorporate them, this WRO is a signal to act—whether or not Zijin is in your current supply chain. Where CBP investigates one producer in a sector, scrutiny of that sector tends to follow. 

What a WRO Actually Does to Your Shipment 

A WRO is not a fine or a warning. It is an instruction to every U.S. port to detain the covered merchandise on sight. There is no advance notice to the importer and no phase-in period. The merchandise stops at the border. 

Once your shipment is detained, you have a narrow set of options: 

1. Export the shipment to another country. 
2. Destroy the shipment under CBP supervision. 
3. Prove the negative—submit detailed documentation demonstrating that the specific merchandise was not produced with forced labor, or not subject to the WRO, and secure its release. 

The third option is the only one that recovers the value of your goods, and it is demanding. CBP expects a complete, traceable supply-chain record: purchase orders, production records, transportation documents, payroll and labor records, and a mapped chain of custody from raw material to finished product. Importers who have not built that documentation in advance rarely assemble it fast enough to beat their demurrage and storage costs. 

The Move Importers Should Make Now—Not After Detention 

Detention is the wrong moment to start your due diligence. By then, your goods are sitting at the port accruing costs while you scramble for records, your suppliers may be slow or unwilling to produce. The importers who weather forced-labor enforcement are the ones who did the work before CBP ever looked at them. 

If copper touches your supply chain, here is where to start: 

1. Map your supply chain to the raw-material source. Identify not just your direct supplier but the upstream producers—and their corporate parents. The Zijin action shows that parent-company history is squarely in scope. 
2. Screen every tier against the UFLPA Entity List, active WROs, and Findings. Then screen the corporate affiliates and parents of those entities. A clean, direct supplier owned by a flagged parent is not a clean supply chain. 
3. Build your documentary defense before you need it. Assemble and retain the production, labor, payment, and chain-of-custody records that demonstrate your goods are clean. CBP’s recently issued Forced Labor Enforcement Operational Guidance for Importers sets out the documentation the agency expects and the enforcement process you will face. 
4. Put contractual protections in place. Require suppliers to warrant the absence of forced labor, to provide supply-chain documentation on demand, and to indemnify you for enforcement losses. These provisions are far easier to negotiate before a detention than after. 
5. Have a detention response plan ready. Know who on your team and which outside counsel will act, what records you will pull, and how quickly—because the clock starts the moment your shipment is held. 

The Bottom Line 

CBP now oversees and enforces dozens of WROs and eight Findings under 19 U.S.C. § 1307, and the Serbia Zijin action shows the agency’s reach expanding in two directions at once: into new sectors like copper, and across borders in pursuit of entities with a forced-labor history wherever they operate. The importers most exposed are the ones who assumed that because they don’t source apparel or solar—or because they moved production out of China—forced labor isn’t their problem. 

It is. The question is whether you find out on your own terms, with your supply chain mapped and your documentation ready, or at the port, with your goods detained and the burden of proof on you. 

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.