The rising popularity of soy wax candles stems from a desire for cleaner, more natural products. Soy wax, derived from soybeans, is widely adopted as an alternative to traditional petroleum-based waxes. Evaluating the safety of a soy wax candle requires looking at the wax itself, its combustion byproducts, and the other materials included in the final product. This article examines the facts about soy wax to determine if it is a non-toxic option for the home.
Composition and Origin of Soy Wax
Soy wax begins as soybean oil, extracted from harvested soybeans. The process involves cleaning, cracking, de-hulling, and rolling the beans into flakes before the oil is removed. Since soybean oil is liquid at room temperature, it must be solidified to function as candle wax.
The oil is transformed into a solid wax through hydrogenation. This chemical process treats the oil with a hydrogen solution, converting unsaturated fatty acids into saturated fatty acids to raise the melting point. While soy wax is often marketed as 100% natural, commercial versions may contain stabilizers or non-soy additives to improve burn performance and scent retention.
Evaluating the Toxicity of Pure Soy Wax Emissions
The core concern with any candle is what it releases into the air. Combustion produces byproducts like soot and volatile organic compounds (VOCs). Studies comparing different waxes, including pure soy wax, found that all types produce similar emission profiles. These emissions are well below levels considered concerning for human health under normal use conditions.
When soy wax burns, it releases particulate matter, or soot, which can affect indoor air quality. Soy wax is often praised for producing less soot compared to paraffin wax, especially when the wick is trimmed correctly. The small amounts of VOCs and particulate matter emitted are not considered hazardous when burned in a ventilated space. Therefore, the wax itself is considered non-toxic.
Comparing Soy Wax to Paraffin and Other Common Waxes
Soy wax gained its non-toxic reputation due to the contrast with paraffin wax. Paraffin wax is a byproduct of petroleum refining. When burned, it can release trace amounts of VOCs such as benzene and toluene. While total emissions from paraffin are below safety thresholds, its non-renewable origin and association with known carcinogens cause consumer concern.
Scientific testing shows that the emission levels of VOCs and particulate matter from pure soy wax and paraffin wax are nearly identical in composition and concentration. This suggests the perceived toxicity difference is often greater in marketing than in combustion science. Other natural waxes like beeswax and coconut wax are also popular. All natural waxes share the benefit of being derived from renewable sources, unlike petroleum-based paraffin.
Hidden Toxicity Sources in Soy Wax Products
Even if the soy wax itself is not toxic, the final candle product may contain hazardous components. The most significant source of potential toxicity in any candle is the synthetic fragrance oil. Many mass-produced candles use synthetic fragrances that can contain phthalates, chemicals used to make scents last longer.
Phthalates are known endocrine disruptors that can interfere with the body’s hormonal systems. Burning these synthetic scents can also release other VOCs, including formaldehyde and toluene, which diminish indoor air quality. Furthermore, some low-quality wicks may contain metal cores to keep them rigid. When these wicks burn, they release heavy metal particles into the air, posing a serious health risk. Consumers concerned about toxicity should seek out candles labeled with phthalate-free fragrances and wicks made of 100% cotton or wood.