Trona is not considered toxic in the traditional sense. It won’t poison you through brief skin contact or small incidental exposures. However, it is classified as an irritant due to its alkaline nature (pH 10.5), and it can cause real discomfort or harm to your skin, eyes, and lungs depending on how much you’re exposed to and for how long.
Trona is a naturally occurring mineral with the chemical name sodium sesquicarbonate. It’s mined primarily in Wyoming and processed into soda ash (sodium carbonate), which is used in glass manufacturing, detergents, and various industrial processes. The mineral itself sits somewhere between baking soda and washing soda in terms of alkalinity, which is what drives most of its health effects.
What Happens if Trona Touches Your Skin or Eyes
Trona solutions are mildly irritating to skin. Prolonged or repeated contact can cause dermatitis, a red, itchy rash that results from the alkaline material stripping oils from the skin’s surface. Workers at trona mining facilities have developed dermatitis from regular handling, though the mineral does not appear to cause true allergic sensitization. Brief, casual contact is unlikely to cause problems beyond mild dryness.
Eyes are more vulnerable. Sodium carbonate, the primary product derived from trona, carries a formal warning for causing serious eye irritation. Trona dust getting into your eyes can cause redness, tearing, and pain. If you get trona dust or a concentrated solution in your eyes, rinse thoroughly with water for several minutes.
Breathing Trona Dust
Inhalation is the most significant health concern, particularly for people who work around trona regularly. A study of trona mine workers found that half complained of upper respiratory symptoms and eye irritation. About 23% reported chronic cough and phlegm production, and a third experienced shortness of breath during mild physical activity like walking uphill.
The study also measured lung function over time. Nonsmoking workers exposed to respirable trona dust showed measurable declines in how much air they could forcefully exhale in one second, a standard measure of lung capacity. Smokers and former smokers fared worse, with more pronounced lung function declines tied to both their smoking history and years of trona dust exposure. These findings suggest that chronic, heavy exposure to trona dust does affect lung health, even in nonsmokers.
For workplace safety, OSHA treats trona as a general particulate and sets the permissible exposure limit at 5 mg per cubic meter of air for the fine respirable fraction, and 15 mg per cubic meter for total dust, measured over an eight-hour workday. There is no special, stricter limit specifically for trona, though regulators considered and ultimately abandoned a proposal for a lower threshold of 0.5 mg per cubic meter back in 1999.
What Happens if You Swallow It
Swallowing a small amount of trona, such as accidentally getting some in your mouth while handling it, is unlikely to cause serious harm. The mineral is alkaline but not strongly caustic. You might experience nausea, mild stomach pain, or an unpleasant taste. Drinking water to dilute it is a reasonable first step.
Larger ingestions of strongly alkaline substances can irritate the lining of the throat and stomach, potentially causing pain, vomiting, difficulty swallowing, and drooling. Trona is far less dangerous in this regard than concentrated lye or industrial-strength caustics, but swallowing significant quantities still warrants medical attention.
How Trona Compares to Baking Soda and Washing Soda
Trona falls between its two more familiar relatives in terms of irritation potential. Sodium bicarbonate (baking soda) is the mildest of the three. It is not a skin or eye irritant and is commonly used in food and personal care products. Sodium carbonate (washing soda, or soda ash) is the most alkaline and is a recognized skin and eye irritant. Trona, as a natural combination of the two, lands in the middle.
A safety review published in a toxicology journal concluded that sodium sesquicarbonate, sodium bicarbonate, and sodium carbonate are all safe as used in cosmetic products. Neither trona nor baking soda showed mutagenic effects in cell culture testing, and neither sodium carbonate nor sodium bicarbonate caused birth defects in animal studies. So while trona is an irritant, it does not appear to be carcinogenic, mutagenic, or otherwise systemically toxic.
Environmental Toxicity
Trona poses low risk to aquatic life at typical environmental concentrations. Toxicity testing on its primary component, sodium carbonate, found that it takes 265 to 565 milligrams per liter to kill half of a daphnia (water flea) population over 96 hours, and 300 to 320 milligrams per liter to reach the same threshold in bluegill sunfish. These are relatively high concentrations, placing trona in the low aquatic toxicity category. Natural waterways near trona deposits, like those in Wyoming’s Green River Basin, have alkaline conditions that local ecosystems have adapted to, though large-scale runoff from mining operations could still shift water chemistry enough to affect sensitive species.
The Bottom Line on Trona Safety
Trona is an irritant, not a poison. For most people encountering it occasionally, the risks are limited to temporary skin dryness, eye irritation, or mild respiratory discomfort if dust is inhaled. The real health concerns apply to workers exposed to trona dust day after day, where cumulative inhalation can measurably reduce lung function over time. If you’re handling trona for a project or job, wearing a dust mask, safety glasses, and gloves will address the main exposure routes.