Methanol is well known and toxic. Industrial alcohol contains about 4% methanol. If it is used as edible alcohol by illegal elements to make fake wine, it will produce methanol poisoning after drinking. The lethal dose of methanol is about 70 ml.
The toxicity of methanol has a great influence on the nervous system and blood system of human body. Intake of methanol through digestive tract, respiratory tract or skin can produce toxic reactions. Methanol vapor can damage human respiratory mucosa and visual acuity. In methanol production plants, the relevant authorities in China stipulate that the concentration of methanol in the air is limited to PC-stel=50mg/m3, PC-TWA=25mg/m3. In the presence of methanol, gas masks must be worn in the field work, and the waste water of the plant must be treated before discharging, allowing methanol with a content of less than 200mg/L.
The poisoning mechanism of methanol is that methanol is metabolized by human body to produce formaldehyde and formic acid (commonly known as formic acid), and then harmful to human body. Common symptoms are drunkenness, headache, nausea, vomiting, and blurred vision hours later. Serious people will lose their sight or even their lives. Causes of blindness: Formic acid, a metabolite of methanol, accumulates in the eye and destroys visual nerve cells. Brain nerves can also be damaged, resulting in long-term damage. When formic acid enters the blood, it makes the tissue more acidic, damages the kidney and leads to kidney failure.