The correct answer is option 3, methyl alcohol. When local made alcoholic beverages are contaminated with methyl alcohol, it can lead to serious health issues including blindness and even death. Methyl alcohol, also known as methanol, is a toxic form of alcohol that is not meant for consumption.

Option 1, vinegar, is commonly used as a household condiment and food preservative. Consumption of vinegar does not normally cause blindness or death, as it is considered safe when used in appropriate amounts.

Option 2, carbolic acid, is a strong disinfectant and is not commonly found in alcoholic beverages. Ingesting carbolic acid would be extremely dangerous and could cause severe health complications, but it is not a likely contaminant in local made alcoholic beverages.

Option 4, formic acid, is a corrosive acid that occurs naturally in certain plants and animals. Ingesting formic acid in high concentrations can cause harm to the body, but it is not a common contaminant in alcoholic beverages.

In conclusion, the presence of methyl alcohol in local made alcoholic beverages is a serious health risk and can lead to blindness or death. It is important to be cautious when consuming such beverages and opt for commercially produced and regulated alcoholic drinks to minimize the risk of contamination.