Let’s start with the defiinition:

“Teapot” oil refineries are small, privately owned oil refineries primarily based in China’s Shandong province. The nickname comes from their physical appearance — they are called “teapots” because of their compact teapot-like shape, which distinguishes them from the massive facilities run by China’s state-owned oil giants like Sinopec and PetroChina.

They’re a big deal in the sanctions world for a few reasons.

First, scale: despite being individually small, they account for about one-quarter of China’s total processing capacity. Collectively they’re a significant chunk of one of the world’s largest oil-refining industries.

Second, they’re the primary channel for sanctioned oil into China. China’s state-owned refiners are cautious about buying Iranian oil because they do not want to be cut off from the U.S. dollar-based international financial system. The teapots, which mostly serve domestic markets, have been willing to take on that risk. As a result, these unassuming teapots handle approximately 90% of Iran’s total oil exports — a figure consistent with today’s Treasury alert, which notes that China purchases roughly 90 percent of Iran’s oil exports with teapots accounting for the majority.

Third, their business model depends on buying cheap. Operating on razor-thin margins, they survive by buying cheap crude wherever they can and refining it into fuel for neighboring provinces. Sanctioned oil from Iran (and Russia) comes at steep discounts, which is precisely what makes it attractive.

The evasion methods are sophisticated. Today’s Treasury alert highlights the use of front companies in Asia and the UAE, intermediary brokers, and a “shadow fleet” of vessels employing tactics like ship-to-ship transfers, falsified documentation, and vessel identity manipulation to disguise the origin of crude shipments.

OFAC has been actively targeting them. The U.S. Treasury recently sanctioned Hengli Petrochemical (Dalian) Refinery, China’s second-largest independent refinery, for generating hundreds of millions of dollars in revenue for Iran’s military. And today’s alert specifically warns financial institutions to conduct enhanced due diligence on transactions involving China-based refineries, particularly in Shandong Province.

In short: teapot refineries are the practical infrastructure through which most of Iran’s oil revenue continues to flow, which is why they’ve become a central focus of OFAC’s maximum pressure campaign.

and here’s a quick and dirty summary of the OFAC Alert issued on Tuesday:

What it is: OFAC issued a formal warning to banks and financial institutions worldwide about the sanctions risks of doing business with China’s independent “teapot” oil refineries, particularly those in Shandong Province.

The core problem: China buys about 90% of Iran’s oil exports, and teapot refineries are the primary buyers. Some of these refineries have even used the U.S. financial system for dollar-denominated transactions and to acquire U.S. goods — creating direct U.S. jurisdictional hooks.

Who’s already been sanctioned: Since the resumption of maximum pressure on Iran, OFAC has designated five teapot refineries by name: Shandong Shouguang Luqing Petrochemical, Shandong Shengxing Chemical, Hebei Xinhai Chemical Group, Shandong Jincheng Petrochemical Group, and Hengli Petrochemical (Dalian) Refinery. Their U.S.-connected property is blocked, and the 50% ownership rule applies to their subsidiaries.

What OFAC wants banks to do: Three things, essentially — screen for transactions involving designated teapot refineries or others that may be importing Iranian oil; conduct enhanced due diligence on transactions with China-based refineries (especially in Shandong); and communicate sanctions compliance expectations clearly to correspondent banks in China.

The evasion playbook OFAC is flagging: The alert lays out the specific methods Iran uses to get oil to these refineries undetected. These include front companies in Asia and the UAE that broker shipments and receive payments; middlemen — typically Asia-based companies with vague stated business purposes — acting as brokers between Iranian sellers and teapot buyers; a “shadow fleet” of tankers using deceptive shipping practices like ship-to-ship transfers to obscure cargo origins; blending Iranian oil with oil from other countries and forging documents to relabel it as “Malaysian blend”; and vessel identity manipulation, including reporting data from non-sanctioned or scrapped “zombie vessels” to mask a ship’s true identity.

The implicit threat: The alert makes clear that OFAC is prepared to deploy secondary sanctions against foreign financial institutions that continue to support Iran’s oil trade. This is a signal to non-U.S. banks — particularly in Asia — that facilitating these transactions carries real consequences, even if the bank has no direct U.S. presence.

The bottom line for compliance teams: if you’re processing transactions involving Chinese refineries, particularly independent ones in Shandong, OFAC considers that a high-risk activity warranting enhanced scrutiny.