I believe mineral oil is the better and safer finish for cutting boards. Linseed oil is toxic and should not come into contact with eatable foods.
Toxins in Wooden Furniture
Finding nontoxic wooden furniture can actually be just as challenging as finding a nontoxic sofa, even though you don’t have to worry about flame retardants. Choosing only solid wood pieces is a great start (lots of “wooden” furniture is really made of particle board or plywood which is glued together with formaldehyde-releasing adhesives), but the finishes can be another big problem.
One area of confusion for lots of folks is around linseed oil. Is this truly a nontoxic wood finish, or just Sneaky Stuff?
Here’s the deal with linseed:
Based on our research, we feel that pure, 100% linseed oil poses little, if any, toxic threat to human health, even though it does emit an odor as it dries. Material Data Safety Sheets (MSDS) on linseed oil tell us that it is non-toxic, and various other sources confirm this.
Boiled Linseed Oil
Beware of “boiled linseed oil.”
The confusion around linseed oil arrives when with “boiled linseed oil,” which is what’s found in most stores/home-centers is confused with 100% linseed oil.
Basically, there are three types of linseed oil, two of which are non-toxic.
1) Raw linseed oil is, in fact, flax seed oil. It takes a long time to dry but is entirely non-toxic.
2) The polymerized version is true “boiled” linseed oil, sometimes called “stand oil”. Stand oil is generated by heating linseed oil near 300 °C for a few days in the complete absence of air. Under these conditions, a is highly viscous product results, which provides exceptionally uniform coatings that “dry” to more elastic coatings than linseed oil itself. It also dries much more quickly (although still more slowly than toxic, commonly-used polyurethanes.) This true boiled linseed oil is also non-toxic.
3) The “boiled linseed oil
” you can buy in most stores is actually mostly raw linseed oil, but with plasticizers, hardeners, and heavy metals added to make it act like true boiled oil, without the time and effort it takes to actually boil it; in other words, it’s cheap. Folks who are concerned about the toxicity of linseed oil are likely thinking of this type.
We’ve identified two sources for good linseed oil: Heritage Natural Finishes and Earthpaint.