Taiwan has charged 15 executives and four food companies over cooking oil contaminated with a known cancer-causing chemical — bad news for the companies, their customers, and anyone who bought the products.

• Chung Lien Oil loosened its quality rules for imported Brazilian soybeans, letting in beans far more likely to produce benzopyrene during processing.
• Executives learned test results were abnormal but kept shipping, waiting weeks before telling regulators.
• Fu Shou, Fwusow, and Taisun kept bottling, blending, and selling the bad oil to restaurants and shoppers after learning about the problem.
• Chung Lien also under-reported how much tainted oil it made — by more than half — which threw off the recall.
• Prosecutors want the courts to seize about NT$887 million in profits and hand down heavy sentences.

Outlook: Expect a drawn-out court fight, wider recalls, and tighter scrutiny of Taiwan's edible oil supply chain.