The gases released by rotting potatoes can be deadly, but only when toxic and suffocating gases accumulate in an enclosed, unventilated space. The threat does not come from merely catching a whiff of a spoiled potato in a kitchen. Fatalities have been recorded in places like root cellars or deep storage bins where large quantities of potatoes have been left to decay.
The Specific Toxic Compounds in Rotten Potatoes
Decaying potatoes pose a danger due to two distinct types of toxic compounds: glycoalkaloids and fermentation gases. Glycoalkaloids, primarily solanine and chaconine, are natural defense mechanisms in potatoes, which are members of the nightshade family. These compounds are concentrated in the peel, sprouts, and green areas that develop from exposure to light or physical damage.
Glycoalkaloids pose a serious risk if the spoiled potato is eaten. A toxic dose is estimated to be as low as 2 to 5 milligrams per kilogram of body weight. These compounds are non-volatile, meaning they do not easily evaporate into the air to form an inhalable poisonous gas. Therefore, the common notion of “solanine gas” being the lethal inhalant is scientifically inaccurate.
The lethal inhalation risk comes from anaerobic decomposition, where bacteria break down potato starch without oxygen. This process releases a mixture of gases, most notably large amounts of Carbon Dioxide (\(\text{CO}_2\)) and Hydrogen Sulfide (\(\text{H}_2\text{S}\)). Carbon dioxide is an odorless, heavy gas that acts as a simple asphyxiant by displacing breathable air. Hydrogen sulfide is the source of the foul, rotten-egg smell associated with decay, and it is a potent, fast-acting chemical poison.
How These Toxins Affect the Human Body
Hydrogen sulfide (\(\text{H}_2\text{S}\)) is the primary acute risk associated with the smell of decay, acting as a broad-spectrum poison on the nervous and respiratory systems. At low concentrations, the gas is easily detectable by its offensive odor, causing symptoms like nausea, headaches, and eye irritation. However, at concentrations between 100 and 150 parts per million (ppm), \(\text{H}_2\text{S}\) paralyzes the olfactory nerve. This instantly deadens the sense of smell and gives a false sense of safety.
High concentrations, particularly above 800 ppm, are immediately life-threatening, causing rapid unconsciousness, known as “knockdown.” The gas interferes with cellular respiration, preventing cells from utilizing oxygen. This leads to respiratory failure and death within minutes. Separately, ingesting high levels of glycoalkaloids causes severe gastrointestinal distress, including vomiting and diarrhea, and can lead to neurological effects such as confusion and paralysis.
When Rotten Potatoes Become Life-Threatening
The critical factor that transforms a bad smell into a lethal hazard is the environment in which the decay occurs. The gases produced by decomposition, Carbon Dioxide and Hydrogen Sulfide, are both heavier than ambient air. In a well-ventilated room, these gases disperse harmlessly. However, in a closed space, they settle and accumulate near the floor.
Areas like deep storage bins, poorly ventilated pantries, or root cellars are ideal locations for these dense gases to pool. As \(\text{CO}_2\) accumulates, it displaces oxygen, creating an oxygen-deficient atmosphere that can cause asphyxiation. When \(\text{H}_2\text{S}\) reaches toxic concentrations in these confined spaces, a person entering may be overcome immediately, unable to call for help or escape. Fatality occurs not from the potato itself, but from entering an environment where the heavy, invisible gases have reached a lethal concentration.
Safe Storage and Disposal Practices
Preventing this dangerous scenario starts with proper storage designed to minimize spoilage. Potatoes should be kept in a cool, dark, dry, and well-ventilated area, ideally between 45 and 50 degrees Fahrenheit. Good ventilation is necessary to prevent moisture buildup and allow any naturally occurring gases to disperse safely.
Regularly inspect stored potatoes and immediately remove any that show signs of greening, sprouting, or softness. Once a potato begins to rot or develops a moldy, soft, or mushy texture, it should be discarded promptly. To ensure safety, spoiled potatoes should never be thrown into an indoor trash can. They should be placed in a sealed bag and disposed of in municipal waste or an outdoor compost system where released gases can escape into the open air.
Never enter a basement, root cellar, or storage area where a strong, rotten smell is present. Always ensure the area has been thoroughly ventilated first.