Question from Z. X.

I’ve seen many recipes for cleaning items using Fels Naptha soap. Do you have any idea of whether this has toxic ingredients?

Debra’s Answer

100 years ago, Fels-Naptha was the most commonly used laundry soap. It is hard to find now, but is still available on the internet, if not at your local grocer. Often it is misplaced with the bar soaps for handwashing rather than in the laundry section. It is still used today for poison ivy treatment, garden fertilizer and insecticide as well as laundry detergent and for stain removal.

When Fels Naptha was first made, most soap was made from tallow and lye. Tallow was obtained by boiling and filtering butchered fat from cows, pigs, chickens, horses, and other animals.

Today the label lists “cleaners, soil and stain removers, chelating agents, colorants, and perfume” as the ingredients. The warning on the label says, “CAUTION: EYE AND SKIN IRRITANT. Avoid contact with eyes and prolonged contact with skin. Keep Out Of Reach Of Children.

I contacted the manufacturer Dial Corp to get the Material Safety Data Sheet MSDS. In addition to soap dust, the only other hazardous ingredient listed was “Hydrocarbons, Terpene processing by-products CAS# 68956-56-9.” I was unable to find any information on the toxicity of this chemical. My standard databases just said things like “not enough data available”. But it is a petrochemical ingredient.

The MSDS for Fels Naptha from the National Institutes of Health Household Products Database was slightly different. Under “Chronic Health Effects” it says, “Chronic toxicity testing has not been conducted on this product. However, the following effects have been reported on one of the product’s components. Stoddard solvent: Repeated or prolonged exposure to high concentrations has resulted in upper respiratory tract irritation, central and peripheral nervous system effects, and possibly hematopoetic, liver and kidney effects.” Stoddard solvent is another name for mineral spirits, which are, like petroleum distillates, a mixture of multiple chemicals made from petroleum. Exposure to Stoddard solvent in the air can affect your nervous system and cause dizziness, headaches, or a prolonged reaction time. It can also cause eye, skin, or throat irritation.

Both MSDS’s note that the ingredients are not identified as carcinogens or potential carcinogens. Their health effects rating is 1, which is “slight.”

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