Rice wine with excessive chemical substances added to it killed five people and sent 23 to hospital between Saturday and Monday in the central province of Ninh Thuan, a local health official said on Wednesday.

A chemical usually used in paint and fuel, methanol is highly toxic for humans. As little as 100 milliliters of methanol can cause blindness.

Vietnam limits methanol to 0.1 milligrams per liter for liquor.

The samples of rice wine, locally known as ruou trang, were also found containing aldehyde, another toxic chemical, in quantities seven times higher than regulated 20 milligrams per liter, according to the tests conducted at the Pasteur Institute in the central province of Khanh Hoa’s Nha Trang.

Nguyen Nhi Linh, director of Ninh Thuan Preventive Health Department, said high levels of methanol and aldehyde could cause swollen liver, mental paralysis, and blindness, not to mention death in a few hours.

According to the health department, two of the 23 people hospitalized were at risk of becoming blind.

Reported by Thien Nhan