The United States has imposed heavy tariffs on Chinese MDI, with preliminary duty rates for a leading Chinese industry giant set as high as 376%-511%. This is expected to impact export market absorption and may indirectly intensify pressure on domestic sales.

The U.S. announced preliminary results of its anti-dumping investigation into MDI originating from China, with the exceptionally high tariff rates stunning the entire chemical industry.

The U.S. Department of Commerce determined that Chinese MDI producers and exporters sold their products in the U.S. at dumping margins ranging from 376.12% to 511.75%. The leading Chinese company received a specific preliminary duty rate of 376.12%, while several other Chinese producers that did not participate in the investigation face a nationwide uniform rate of 511.75%.

This move means that, pending a final ruling, relevant Chinese companies must pay cash deposits to U.S. Customs—amounting to several times the value of their products—when exporting MDI to the United States. This effectively creates a nearly insurmountable trade barrier in the short term, severely disrupting normal trade flows of Chinese MDI to the U.S.

The investigation was initially initiated by the “Coalition for Fair MDI Trade,” composed of Dow Chemical and BASF in the U.S. Its core focus is trade protection against Chinese MDI products being sold at low prices in the American market, demonstrating clear bias and targeting. MDI is a significant export product for the leading Chinese company, with exports to the U.S. accounting for approximately 26% of its total MDI exports. This trade protection measure substantially impacts both the company and other Chinese MDI producers.

As a core raw material for industries such as coatings and chemicals, changes in MDI trade dynamics directly affect the entire domestic industrial chain. China’s exports of pure MDI to the U.S. have plummeted over the past three years, dropping from 4,700 tons ($21 million) in 2022 to 1,700 tons ($5 million) in 2024, nearly eroding its market competitiveness. Although polymeric MDI exports have maintained a certain volume (225,600 tons in 2022, 230,200 tons in 2023, and 268,000 tons in 2024), transaction values have fluctuated sharply ($473 million, $319 million, and $392 million respectively), indicating clear price pressure and continuously shrinking profit margins for enterprises.

In the first half of 2025, the combined pressure from the anti-dumping investigation and tariff policies has already shown effects. Export data from the first seven months reveals that Russia has become the top destination for China’s polymeric MDI exports with 50,300 tons, while the formerly core U.S. market has fallen to fifth place. China’s MDI market share in the U.S. is being rapidly eroded. If the U.S. Department of Commerce issues a final affirmative ruling, major Chinese MDI producers will face even harsher market pressure. Competitors like BASF Korea and Kumho Mitsui have already planned to increase exports to the U.S., aiming to capture market share previously held by Chinese companies. Simultaneously, MDI supply within the Asia-Pacific region is expected to tighten due to redirected exports, leaving domestic Chinese companies facing the dual challenge of losing overseas markets and encountering volatility in the local supply chain.