Tung oil is one of the most commonly used natural wood finishes among woodworkers, but the question often comes up “Is Tung oil food safe?” If you’re working on kitchen countertops, cutting boards, or other items that come into contact with food, then you’ll want to be sure your wood finish isn’t toxic.
The answer depends slightly on what type of product you’re working with. 100% pure Tung oil is completely food safe, as it’s a natural and non-toxic product. Tung oil with solvents and other chemicals added is not the same thing and is only considered food safe once it completely cures.
Let’s take a closer look at Tung oil’s food safety, and what you need to consider when reaching for that product labeled ‘Tung oil’ on your hardware store’s shelf.
Different Products Called Tung Oil
As mentioned, there are multiple formulations sold under the ‘Tung oil’ umbrella.
The three main types are pure Tung oil, wiping varnishes, and oil/varnish blends.
Pure Tung Oil
Pure Tung oil is all-natural and FDA-approved for food contact. It’s a drying oil that provides a durable and long-lasting finish and contains no additives or metallic dryers, so it naturally takes a long time to fully dry and cure.
This oil may be completely natural and additive-free, but this comes at the cost of application ease. Pure Tung oil is notoriously slow and difficult to apply, as it requires 3 to 6 coats, with each one taking at least 2 to 3 days to dry.
Tung oil also has a strong odor that some people find offensive, although this will dissipate over time as the finish dries completely.
Next, we have Tung oil and varnish blends. These formulations combine the rich color and protective qualities of pure Tung oil with the ease of application of typical wood varnishes. The exact formulation will depend on the specific manufacturer, but typically it will contain some form of petroleum-based solvent or mineral spirit.
These blends will dry and cure significantly faster than pure Tung oil will, making them much easier to apply. However, they are not considered food safe until they are fully cured and the solvent has completely dissolved.
While the blend is curing, the solvent will be off-gassing and will release VOCs (volatile organic compounds), which can be harmful – especially to people with sensitivities.
Next up, we have the wiping varnish version of Tung oil. This is a formulation that contains an oil that’s cooked with resins. They also contain a thinner than makes application fast and easy.
They are similar in terms of drying times and ease of application to the oil/varnish blends but feature one major difference. Wiping varnishes are designed to ‘wiped on’ and then left to dry, while blends will specify that they should be wiped or buffed clean after the oil is allowed to penetrate for a set period of time.
Tung Oil Food Safety
When it comes to food safety, it makes sense to err on the side of caution. The good news is that Tung oil is completely safe to use once it cures completely.
The FDA has approved the use of pure Tung oil for food contact. That means any surfaces that come in direct contact with food such as cutting boards, countertops, and dining tables can be treated safely with Tung oil.
As far as pure Tung oil is concerned, it’s considered completely food safe and non-toxic, while both oil/varnish blends and wiping varnishes are considered food safe once the solvent has evaporated.
While the oil blend is drying, it should be kept in a well-ventilated area until the solvent has evaporated, leaving a hardened protective resin. As the oil blend dries it will off-gas and emit harsh and potentially unhealthy fumes, so it’s best to keep it in a workshop or shed during this process.
Is Tung Oil Toxic?
Tung oil is non-toxic and doesn’t contain VOCs (volatile organic compounds). However, some people report reactions to contact (or even breathing vapors) with pure Tung oil.
Tung oil blends containing polyurethane solvents are toxic and should be handled with care and used in well-ventilated areas. Once the solvent has dissolved, and the finish has cured the toxic compounds are no longer present and the surface becomes food safe.
Is Tung Oil Toxic to Animals?
While pure Tung oil is food-safe and non-toxic, you still don’t want to be slurping it up or drinking it. For people, this is not really an issue, but dogs and cats may end up ingesting it if you’re not careful.
Pure Tung oil is not toxic to animals but causes GI upset if ingested in large enough quantities. If you’re applying it to flooring or outdoor furniture, keep pets away from the area until the finish has cured.
You can safely apply Tung oil to dog or cat bowls and the like, just be sure they’ve cured completely before using them.
Tung oil blends containing solvents are toxic to humans as well as animals, so be extra careful with pets around while working with these blends.