In late June 2026, Taiwan-based oil refiner Chung Lien Oil was found to have produced soybean salad oil containing benzo[a]pyrene (BaP) at 8.1 μg/kg — more than three times the legal limit of 2.0 μg/kg. BaP is classified as a Group 1 carcinogen by the International Agency for Research on Cancer.
As of July 19, seven batches of crude oil had been confirmed non‑compliant, totaling approximately 8,000 tonnes of contaminated oil — equivalent to nearly three months of Chung Lien’s production capacity. The company has been ordered to suspend operations and may not resume production until the contamination source is identified and its corrective plan is approved by the competent authority.
The 48‑day reporting delay and the NT$165 million fine
It took 48 days from the time downstream manufacturer Namchow first detected anomalies through its own testing on May 13 to Chung Lien’s official notification to the regulatory authorities on June 30. Chung Lien had actually been informed by its upstream supplier Fwu Shou on June 11 but delayed reporting until June 30 — a gap of 19 days.
In addition, Chung Lien deliberately omitted one batch of abnormal oil produced on April 1 from its official declaration to the authorities, leading to charges of concealment and false reporting.
The Taiwan Food and Drug Administration (TFDA) imposed a record fine of NT$165.2 million on Chung Lien, the highest food‑safety penalty in Taiwan’s history. The Taichung City Government added a separate fine of NT$3 million, while downstream brands Tai Sun, Fwu Shou, Formosa Oilseed, and Namchow each received fines ranging from NT$3 million to NT$6 million.
BaP source: raw material thermal damage or refining process failure?
The exact origin of the BaP contamination remains undetermined, with two main technical hypotheses under investigation.
One hypothesis points to the raw material. The affected batches used Brazilian soybeans, which may have had high moisture content at harvest. During storage drying or fumigation, exposure to temperatures above 200°C could cause thermal damage to the bean, leading to lipid pyrolysis and BaP formation, which then enters the crude oil during solvent extraction.
The other hypothesis focuses on the refining process. The deodorization step in soybean oil refining typically operates at 240–270°C under high vacuum. If temperature distribution within the distillation tower is uneven, vacuum pressure fluctuates, or bleaching earth activity is abnormal, precursors in the oil (such as sterols and triglyceride oxidation products) may undergo cyclodehydrogenation to form BaP in situ. If the deodorizer distillate is not efficiently separated, BaP can also reflux into the finished oil. Chung Lien’s technical team is now comparing deodorization tower temperature profiles and vacuum records from April to June against moisture data from each imported soybean batch. An official conclusion is expected in early August.
Scope of impact and product recalls
The contaminated crude oil was blended and packaged by three major downstream brands — Tai Sun, Fwu Shou, and Formosa Oilseed — and subsequently entered supermarket shelves, baking ingredient supply chains, school lunch programs, and military mess halls. The number of affected downstream businesses grew from an initial 22 to more than 360, with 401 product items placed under preventive recall as of July 20.
On July 7, the Ministry of Health and Welfare waived the previously set 20% usage threshold and ordered a comprehensive preventive recall of all affected products. The Taichung District Prosecutors’ Office has filed a motion with the court to seize real estate assets belonging to Chung Lien and the three downstream companies, and the court has granted the order.
Three technical weaknesses exposed in the industry
Incoming raw material testing lacks BaP risk indicators
Current incoming soybean testing focuses on acid value, peroxide value, and moisture content — parameters that reflect oil oxidation and water levels but cannot detect the risk of BaP from thermal damage. If imported soybeans have already suffered hidden thermal damage during storage drying at origin, these routine tests may still show “pass,” but BaP can be released during refining. The industry needs to introduce rapid screening methods for thermal‑damage markers at the raw material receiving stage.
No real‑time BaP monitoring during refining
BaP detection currently relies on laboratory GC‑MS analysis, which takes 3 to 5 days from sampling and sample preparation to final report. This means companies can only perform end‑product spot checks — a reactive approach that cannot detect anomalies during deodorization in real time or allow immediate process adjustments. The industry needs to develop risk‑prediction models based on process parameters such as deodorization tower temperature and vacuum level, shifting the detection point from the finished product back to the manufacturing process.
Batch traceability lacks sufficient resolution
The current traceability system links crude oil production batches to downstream packaged products only at the “batch” level. Once a crude oil batch is confirmed non‑compliant, investigators must manually check all downstream products associated with that batch, a process that takes days. If the traceability unit were refined from “batch” to daily production time slots and individual deodorization units, and linked instantly to downstream finished goods, it would theoretically be possible to lock down affected products within 48 hours. This requirement is technically feasible and cost‑manageable, but has not been mandated industry‑wide.
As of July 20: no conclusion, investigation ongoing
The official investigation has not yet determined whether the primary cause was raw‑material thermal damage or refining‑process failure. Chung Lien has stated that it has convened technical experts and academics to comprehensively review process conditions, soybean quality, and raw material origins.
The TFDA has said that production may not resume until the cause is identified, and has stepped up BaP testing frequency for both imported soybeans and refined oils. A final investigation report is expected in early August. While the 8,000 tonnes of contaminated oil represent less than 1% of Taiwan’s annual edible oil consumption, and thus have limited impact on overall supply, the incident has clearly highlighted the need for improvements in process monitoring, raw material inspection, and traceability systems across the refining industry.
