THE HAZARDS OF HIDE TANNING
As natural tanners, we snootily called chrome-tanning “chem-tanning.” I get that, and I love our little niche of natural ingredients and the incredible variations they create. But. We do work with chemicals in natural hide tanning. And even with non-chemical natural ingredients, natural doesn't necessarily mean safe (it also doesn't always mean high quality, but that's an HTOTM for another time). Let's explore.
1. Smoke
One of my teacher's teachers (I won't name them here) has been hide tanning his whole life, over seven decades. His smoke set-up for many years has been a windowless room with a benson burner underneath his hide-container. He puts his punk wood on the benson burner and every few minutes, when it gets burned up, he goes into the smoky room and puts more on. He's been able to create consistency and brilliancy in the colours of his smoked buckskins. He also developed COPD..
If you're unfamiliar with COPD I recommend you read into it more. It's typically associated with smoking cigarettes, but inhaling any smoke regularly will harm our lungs. The reason is twofold: aldehyde chemicals and partially burned particulate matter. In other words, the makeup of smoke itself is toxic to us: aldehydes narrow airway openings and damage the lung cells. And the minute physical forms floating in smoke are irritating to us: particulates can get lodged in the lungs for a long time.
Smoking hides outdoors mitigates the hazards of smoke. I often smoke hides indoors because of fire bans in my local municipality. When I do this, I open all the doors and windows, plug in an area fan, and wear a K95 mask.
2. Alum
Alum has a bad rap in some corners of the tanning world, often mis-identified as a chemical (it's a mineral) with the suspicious connotations associated with chemicals. What makes alum a hazard is not any innate toxicity. Similar to smoke, it's the particulates.
We don't want to inhale alum particles, and this will happen if we use it carelessly. To prevent inhaling alum, apply it directly to a hide rather than sprinkling it into a water bath. Start with a wet hide so alum immediately absorbs and doesn't fluff up into the air as you agitate it.
Alum will absorb into our skin as well. I haven't found a clear parameter of the ‘window of tolerance’ of alum toxicity (ie the concept that everything is beneficial and toxic, depending on the dose; including oxygen, water, food, etc.). Alum is used in pickling and as a water purifier, so small amounts are definitely okay to ingest and absorb. Stay on the cautious side by wearing gloves when handling it.
3. Alkalis
The two popular alkalis for bucking hides are lime (calcium hydroxide) and lye (either sodium hydroxide or potassium hydroxide). These are chemicals. They both are potentially damaging when in direct contact with skin and when inhaled as particulates.
Of the two, lye is more caustic. It will irritate exposed skin to the point of potentially burning and blistering it. Lime will more often dehydrate and annoy the skin, but some people are more sensitive to it. Always wear gloves when handling alkalis and when turning hides over in a bucking solution.
To avoid inhaling lye or lime particles, mix their powders into water on a 1:1 ratio of volume (ie 2 cups lime powder, 2 cups water). The water will stabilize the powder. And wear a KN95 if working with a high volume of alkalis.
4. Bugs-Bacteria-Infections
Animals may have parasites on their skin or in their bodies when they are harvested. These can transfer to you if the parasites quickly look for a new host.
The most common parasite is the tick. Ticks may dislodge from a hide after it's skinned once they stopped receiving nutrients and crawl to a new host. Unlike the six-legged keds - which are much more common, are often mistaken for ticks, and tend to stay on the hide long after harvest - ticks can jump from one species to another. So yes, they can come for you. Check yourself for ticks after skinning an animal; shake hides vigorously after skinning or receiving a hide.
Internal parasites can include tapeworm (echinococcus), toxoplasma gondii, trichinella, and parapoxvirus. We can contract these mainly from eating infected, undercooked meat but some infections like those caused by anthrax bacteria can travel rapidly via contact. It's wild how many hunters will take down an obviously sick animal. In Montana one year, a hunter harvested a deer severely sick with anthrax who was already on the brink of death. The hunter still brought the animal into a game processor for butchering. This caused mayhem for dozens of people who had to respond to the situation. You cannot necessarily trust that a hunter who gives you a hide has harvested an animal safely, so get acquainted with the diseases impacting animals local to you and know the signs of infection.