Hungary Halts Polluting Battery Plant

Groundwater beneath a Chinese-owned battery factory in Debrecen, Hungary, contained aluminium at 2,676,000 micrograms per litre, more than 13,000 times the legal limit (444, Portfolio). Arsenic, lead, cadmium, cobalt and nickel were also above permitted levels. Hungarian authorities suspended production at Semcorp Hungary on 24 June and, by 3 July, banned all activity on the site (HVG). Debrecen is the city Hungary has sold to investors as Europe’s largest battery-manufacturing cluster. Semcorp was one of the suppliers feeding that system (G7/Telex).

Why a thin film can stop a car factory

Semcorp makes separator film, the thin porous membrane that sits between the positive and negative sides of a battery. It allows lithium ions to move during charging and discharging, while preventing the two sides from touching. If they touch, the cell can short-circuit and enter thermal runaway, the chain reaction in which a battery overheats uncontrollably (Element). If the film tears, absorbs moisture or is contaminated, the cell becomes a safety risk.

That is why Debrecen’s battery cluster was built around close suppliers. Semcorp’s plant, with more than 440 employees, sits near CATL, Eve Power, EcoPro BM and BMW in the city’s Southern Economic Zone (Telex). BMW assembles high-voltage batteries on site to cut logistics costs (Népszava). A nearby separator supplier means cleaner handling and more predictable delivery. But the same proximity creates a hard dependency: when the local supplier is shut, there is no easy substitute next door.

Europe can put battery plants on European soil, but it still depends heavily on Chinese companies for some of the inputs those plants need. Chinese producers controlled 89.6% of the global battery separator market in January-April 2026 (SNE Research). The dependence does not disappear because the factory is inside the EU. It simply moves inside the EU’s industrial map.

Regulators saw a warning in February. The shutdown came in June.

Inspectors found an unidentified steaming, foul-smelling liquid entering the ground during a site visit on 26 February. Sampling was ordered in March, laboratory results arrived on 14 May, and the breach was formally established on 22 May. Production was suspended only on 24 June (444, Portfolio). Semcorp had described the liquid as harmless condensate. The laboratory findings, showing heavy-metal contamination across thirteen substances, said otherwise.

The row has exposed the weak point in Hungary’s governance model. Debrecen mayor László Papp publicly told Semcorp to leave the city and filed a criminal complaint (HVG). The national government demanded his resignation. Papp replied that the government office, not the municipality, had permitted the plant and held monitoring data long before the public knew about the contamination. The unresolved question is familiar well beyond Hungary: who carries responsibility when the national state grants permits, but the locality lives with the damage?

Who pays if this drags on

The first losers are Semcorp’s 440-plus workers and Debrecen’s residents, whose groundwater now carries heavy-metal contamination. The next risk sits with car and battery plants. Mercedes has already seen what happens when a Debrecen battery node stops delivering: delays at CATL’s local plant forced it to source batteries from China by sea, adding around six weeks to delivery (auto motor und sport). That case involved CATL, not Semcorp, but the vulnerability is the same. When local supply breaks, the fallback wipes out the advantage the cluster was built to provide.

Slovakia and Czechia, tied into the same German-led automotive production network, could feel the knock-on effect if Hungarian battery inputs are delayed. Poland, already Europe’s largest lithium-ion battery producer through LG Energy Solution’s capacity near Wrocław (Notes from Poland), could benefit if Hungary’s model starts to look less reliable. There is no evidence yet that orders or investment are moving.

The missing fact is still the most important one: whether any downstream plant has already lost production because of the shutdown. The EU’s Battery Regulation (2023/1542) tightens environmental and due-diligence rules for batteries sold in Europe. Hungary’s test is whether it can enforce those rules without undermining the speed and certainty it promised to investors.