The confusion about whether hemlock wood is poisonous stems from a shared name applied to two entirely different biological entities. The wood used in construction and woodworking is not poisonous. However, “hemlock” also refers to a highly toxic plant that remains a serious threat to livestock and humans. This distinction is necessary to understand the safety of the lumber you may encounter.
The Critical Distinction Between Hemlocks
The confusion arises because the common name “hemlock” is used for both a large, non-toxic tree and a small, extremely poisonous herb. The wood you buy comes from the Hemlock tree, which belongs to the genus Tsuga. Species like Western Hemlock and Eastern Hemlock are commercially harvested for their soft, straight-grained wood. This timber contains no known systemic toxins harmful to humans or animals.
Conversely, the plant known as Poison Hemlock (Conium maculatum) is the source of the toxicity. This is a biennial flowering herb, not a tree that produces lumber. This plant contains potent neurotoxic piperidine alkaloids, primarily coniine, which can cause severe illness or death if ingested. The notorious poison used to execute the Greek philosopher Socrates was derived from this highly toxic plant.
The Poison Hemlock plant is herbaceous, meaning it has no woody parts and is not the source of any commercial lumber. The toxicity is concentrated in its leaves, seeds, and roots, with all parts of the plant being dangerous. The Tsuga tree and the Conium plant are completely unrelated biologically, sharing only a common name.
Safety When Handling Hemlock Wood
When handling lumber from the Hemlock tree (Tsuga species), there is no risk of systemic poisoning. The wood itself does not contain the deadly alkaloids found in the Poison Hemlock plant. Ingesting a splinter or small amount of the wood would not lead to the respiratory paralysis associated with the plant’s toxins.
The primary safety concerns with Tsuga lumber relate to physical and respiratory irritation, similar to handling any other untreated wood. Sawdust generated during cutting or sanding can irritate the eyes, skin, and respiratory system. Prolonged exposure to wood dust is classified as a human carcinogen, linked to nasal and sinus cancers, which necessitates proper ventilation and protective equipment. The usual mechanical hazards of woodworking, such as splinters, also apply.
Safety When Burning Hemlock Wood
Hemlock wood is safe to burn as firewood and does not release any poisonous fumes beyond the standard byproducts of wood combustion. It is a softwood species, meaning it is a serviceable but not premium fuel source. Like all softwoods, it may contain a higher resin content compared to hardwoods, which can contribute to creosote buildup in chimneys.
The main risk when burning any type of wood, including hemlock, is improper combustion and ventilation. Burning wood that is not adequately dried, or “seasoned,” produces more smoke, which is never safe to inhale. Standard safety practices, such as ensuring proper chimney maintenance and using a carbon monoxide detector, should always be followed.