What are the main health risks of drinking liquor from small workshops?

What are the main health risks of drinking liquor from small workshops?
Small-scale workshop liquor poses two distinct toxicological hazards: methanol and fusel oil. Methanol itself is metabolized into formic acid, which inhibits mitochondrial cytochrome oxidase, causing metabolic acidosis and damaging the heart, kidneys, and retina—oral doses of 100 mg/kg can poison, and 0.3-1 g/kg can be lethal. Fusel oil, composed of propanol, isobutanol, and isoamyl alcohol, is more toxic than ethanol and metabolizes slower. It crosses the blood-brain barrier and accumulates in the brain, stimulating nerves and causing vascular congestion, which manifests as persistent headaches even after ethanol has cleared. Unlike regulated industrial distilleries that monitor these compounds via gas chromatography, small workshops often lack quality control, making their products a higher-risk category for both acute methanol poisoning and chronic fusel-oil-related neurological discomfort.