How Cesium-137 Tainted Shrimp, Spices and Sneakers: Inside Indonesia’s Radiation Probe

A widening contamination case with global stakes

Indonesia has launched a criminal investigation after traces of the radioactive isotope cesium 137 were found in exports as varied as frozen shrimp, cloves and branded sneakers. The detections, first flagged in Europe and the United States, triggered recalls and import alerts, as well as a sweeping response by Indonesian authorities. Officials stress that the measured levels did not pose an immediate health threat to consumers. They also say the events exposed weak points in industrial oversight and the handling of scrap metal and shipping equipment inside and around a large industrial zone west of Jakarta.

The focus of the probe is the Cikande Industrial Estate in Banten province. Investigators have tied the contamination to a steelmaker, PT Peter Metal Technology, that smelts scrap metal. Government task force officials say airborne particles from activities at the steel plant likely settled on surfaces at nearby facilities, including a shrimp processing site operated by PT Bahari Makmur Sejati. More than 20 factories in and around the estate showed signs of contamination. Nine workers on the estate were found to have been exposed and received treatment in Jakarta. Authorities say all contaminated sites within the zone have been decontaminated.

The trail stretches back to early alerts at ports. Dutch inspectors detected radiation coming from Indonesian shipping containers and reported contaminated boxes of sneakers. In August, U.S. authorities issued a consumer advisory for certain frozen shrimp after cesium 137 was detected in containers that arrived at major ports. A later test confirmed the isotope in a sample of cloves from a different exporter. Those products were recalled and the companies were blocked from sending additional goods until they could demonstrate that the source problem had been fixed.

What investigators say happened at Cikande

Investigators have described a chain of events that starts with scrap metal and ends with microscopic dust. Cesium 137 is a man made radionuclide produced in nuclear fission. In industry and medicine it is commonly found in sealed sources, often as cesium chloride. If a source enters a scrap stream and is melted, the material can convert into a gas or fine particulates inside a furnace. Those particles can deposit on nearby equipment and buildings, and they can also settle on the surfaces of packages and shipping containers. Technical experts have explained that this scenario fits the pattern seen at Cikande, where a steel plant sits within a short drive of food and consumer goods facilities.

Indonesian authorities designated the estate a serious incident zone to speed containment and cleanup. The national nuclear agency, a government task force, and emergency teams conducted mapping, surface decontamination and medical checks. Officials said the country is coordinating with international partners, including the International Atomic Energy Agency, to ensure transparency and maintain confidence in checks on exported goods.

Airborne dust and contaminated containers

Evidence indicates that at least part of the problem moved with the boxes, not just the goods inside them. U.S. findings showed radiation in several shipping containers as well as on packaging. Indonesian officials ordered contaminated scrap containers to be re exported, and began tightening controls on scrap to prevent further exposures. In one case, 14 containers of scrap were sent back from a Jakarta port, with additional containers originating from the Philippines also slated for return. At another port, inspectors intercepted eight containers of zinc powder from Angola that tested positive for cesium 137. Those containers were re exported and later reported to be idling off the Philippine coast as governments worked out next steps.

Indonesia’s Coordinating Minister for Food Affairs, Zulkifli Hasan, who leads the government task force on cesium 137, warned about the risk of reusing contaminated containers for any product.

Hasan said: “If those containers were used to ship shrimp, the shrimp could be contaminated. And if they’re reused for other goods, that’s dangerous.”

How much radiation was found and what it means for health

Measured values in the U.S. cases provide context. Sampling of a shrimp shipment processed in Indonesia showed 68 becquerel per kilogram (Bq/kg) of cesium 137. A later U.S. test of cloves from a separate Indonesian exporter found 732.43 Bq/kg. For food safety decisions, the U.S. Food and Drug Administration uses a Derived Intervention Level of 1,200 Bq/kg for cesium 137. The detected levels were below that threshold, and authorities said they did not present an acute hazard to consumers. Even so, regulators emphasized that repeated exposure over time to contaminated food or surfaces can raise health risks.

Cesium 137 has a half life of about 30 years. It emits penetrating gamma rays that are easy to detect with port monitors and handheld devices. The isotope behaves in the body in ways similar to potassium, so it tends to distribute in soft tissues. Acute exposure at very high levels can be dangerous, but the issue in this case is chronic low level exposure. That is why testing, cleanup and preventing recontamination of packaging and containers are priorities for regulators.

FDA officials, in public guidance, framed the long term health consideration clearly.

The agency said: “The primary health effect of concern following longer term, repeated low dose exposure (for example through consumption of contaminated food or water over time) is an elevated risk of cancer, resulting from damage to DNA within living cells of the body.”

Why cesium 137 shows up in scrap metal

Indonesia does not operate nuclear power reactors or a weapons program. The sources most likely to carry cesium 137 into civilian supply chains are older medical or industrial devices that use sealed radioactive sources. Examples include industrial gauges, radiography equipment and level or density meters. When such a source is lost from regulatory control and enters the scrap trade, it is called an orphan source. If an orphan source is melted in a steel furnace, the result can be widespread contamination of the furnace and the surrounding environment, and detectable residues on surfaces of goods and containers. Indonesian officials said the highest contamination readings were found inside a furnace at the steel plant in Cikande, which supports the theory that radioactive scrap was melted.

Imported versus domestic scrap debate

Officials have explored two paths for how the radioactive material entered the plant’s input stream. One line of inquiry points to imported scrap after Indonesian inspectors discovered multiple contaminated scrap containers at ports and ordered them re exported. Another view, supported by a senior Industry Ministry official during a parliamentary hearing, is that the scrap could have been sourced domestically, possibly from disused medical equipment, then sold into the plant. Authorities said the company’s management had returned to China, which has complicated interviews and document reviews, and police have opened a criminal case. The government imposed tighter controls on scrap shipments and began screening vehicles and goods moving through the industrial area. Officials said more than 1,500 workers were screened for exposure, nine tested positive and were treated. They added that more than 20 affected plants have completed decontamination, with the remaining sites scheduled for follow up surveys.

Trade fallout and responses by regulators

Food and consumer goods supply chains felt the shock quickly. U.S. regulators published import alerts for shrimp processed by PT Bahari Makmur Sejati and later flagged a cloves shipment from PT Natural Java Spice when testing confirmed cesium 137. Retailers and importers recalled affected products and disposed of them. Footwear shipments that showed traces of radiation were returned to Indonesia for testing. In Europe, Dutch officials intercepted containers and reported contaminated sneakers. These findings prompted a broader screening effort and closer scrutiny of shipping containers linked to the industrial zone in Banten.

To restore confidence, the U.S. invoked an authority that allows it to require import certification for specified products and regions. Shipments of shrimp and cloves from parts of Indonesia now must present a radioactive free certificate before entry. Indonesia’s Ministry of Maritime Affairs and Fisheries is scanning export containers and issuing the certificates agreed with U.S. regulators. The task force placed companies that tested positive on a red list, including PT Bahari Makmur Sejati and PT Natural Java Spice, which can reenter trade after they obtain verification from an accredited third party. Regions such as Java and Lampung were categorized for intensified checks on a yellow list.

Indonesia reports that shrimp exports to the U.S. have restarted with tighter screening. Officials said hundreds of containers have been scanned and more than one hundred cleared to sail. The U.S. remains the largest destination for Indonesian shrimp, so both governments are working to keep trade moving while preventing any recurrence. The certification step, along with port side radiation monitoring and careful control of shipping containers, is intended to lower the risk of contaminated surfaces reaching consumers.

How inspectors in the U.S. and Europe detected the problem

Modern ports use fixed and mobile radiation detectors that scan containers as they pass through gates. Small signals are common and often benign, since many materials emit background radiation. When alarms persist or exceed preset thresholds, inspectors conduct secondary checks with handheld instruments and, if needed, take samples from the cargo or packaging. In the U.S. cases, inspectors traced gamma emissions to container walls and packaging, and then to frozen shrimp from a processor located near the Cikande industrial zone. Clove samples from another exporter were held and tested before they reached store shelves.

Across the Atlantic, Dutch authorities detected radiation in a container that carried sneakers, prompting a recall and fresh scrutiny of footwear shipments. These cross checks illustrate a key point about modern supply chains. A contaminated container can move from one cargo to another. If the container is not isolated and decontaminated, it can spread trace contamination to items that never passed through the original incident zone.

What decontamination and containment look like on the ground

Indonesian officials set up a controlled zone at Cikande to map and reduce radiation to safe levels. The national nuclear agency swept the area with portable detectors, marked hotspots and cleaned surfaces with appropriate methods. Waste from decontamination was handled through a dedicated route and placed in temporary storage at a secured location. The government also designated the steel plant area as an isolation point for contaminated goods and equipment to keep them out of general circulation. Vehicles moving in and out of the estate were checked to prevent tracking of particles beyond the zone.

Authorities said people living near highly contaminated spots were relocated during cleanup. Health teams examined residents and workers, identified nine individuals with measurable exposure and cleared them after treatment and follow up. Officials maintain that the contamination was confined to the industrial estate and that food safety systems remain intact. They said the country is coordinating with international partners on monitoring and reporting, and that port controls will remain strict while the investigation continues.

What exporters and importers should do next

Companies do not control every factor in a complex supply chain, but they can reduce risk with practical steps. Exporters near heavy industry should conduct routine radiation scans at plant gates and loading bays, and add simple surface swabbing of packaging areas if a nearby incident has been reported. Track container identification numbers and avoid reusing boxes that have been linked to contamination until they pass independent checks. Keep product packaging sealed as late as possible in the process, and minimize outdoor storage near industrial stacks. Ask suppliers and logistics partners to confirm that scrap, pallets and containers have not been stored or processed in the affected zone. Maintain records that allow quick traceback, and train staff to spot and report unexpected radiation alarms or unusual labels that indicate the presence of a radioactive source. If something tests positive, isolate it, inform national regulators and request guidance before any cleanup or disposal.

At a Glance

• Police in Indonesia opened a criminal case after cesium 137 was found in exports including shrimp, cloves and sneakers.
• Investigators traced the contamination to a steel plant in the Cikande Industrial Estate that smelts scrap metal.
• More than 20 facilities in and around the estate tested positive and were decontaminated.
• Nine workers or residents showed measurable exposure and received treatment.
• Contamination reached packaging and shipping containers, a key reason goods in different categories were affected.
• U.S. tests measured 68 Bq/kg in shrimp and 732.43 Bq/kg in cloves, both below the FDA intervention level of 1,200 Bq/kg.
• Officials say there was no acute health risk, but they caution against repeated long term exposure.
• Indonesia tightened scrap controls and ordered contaminated scrap containers to be re exported.
• The U.S. now requires radioactive free certificates for shrimp and cloves from parts of Indonesia, with red list companies subject to extra checks.
• Shrimp exports to the U.S. have resumed with hundreds of containers scanned and more than one hundred cleared.
• Indonesia is coordinating with the IAEA and U.S. agencies, and plans continued monitoring to prevent recurrence.