Cedar is a very popular softwood used for many different types of construction, favoured for its aroma, appearance and durability. Cedar wood also has a high oil content (which gives it its powerful odour), and many manufacturers use the wood as an ingredient in natural pesticides, small pet beds and other applications. While cedar is not directly toxic, it can be harmful depending on how people or animals are exposed.
Phenols are some of the common aromatic compounds found in woods like cedar. Typically, these compounds stay sealed away in the sap and oils of the cedar tree. However, when the wood is cut open the fibres are exposed, and the phenols, along with other chemicals, escape into the air. Insects dislike the sharp odour of phenols, which is why cedar chips are often used as bedding for both gardens and small pets like rabbits or gerbils. However, phenol also takes it toll on these smaller animals. When a creature like a rabbit inhales the fumes of the cedar, they absorb the phenol into their body. The body sees the phenols as a toxin, and uses liver enzymes to remove it. Over time this can cause liver damage and possibly even death, while in the short term the presence of these enzymes can interfere with medication, like anesthetics, that are given to these small animals.
Some people are allergic to the oil compounds in softwoods like cedar. People allergic to cedar can develop respiratory problems when they are exposed to it. This can be dangerous when susceptible people use cedar chips without realising the danger, or when children unknowingly play in cedar shavings.
For woodworkers and construction workers, cedar presents a similar danger: cedar dust caused by sawing the softwood. This dust also is rich in the cedar oils and workers are usually much more sensitive to it than to other types of dust. On the skin it can cause dermatitis, and if workers breathe it in it can cause both allergic and nonallergic lung reactions. According to Healthfully.org, cedar dust may even cause cancer.
Cedar wood oil is used as a natural scent and has several therapeutic uses, often in treating skin or muscle conditions topically. However, this oil should never be ingested. If it is, the cedar wood oil can cause intestinal problems, burning sensations and nausea.