Is Cedar Toxic? Sawdust, Oil & Pet Bedding Risks by Cedar Type

Cedar is not a generally poisonous wood, but western red cedar dust is a documented cause of occupational asthma, and cedar shavings are a poor choice for pet bedding. The risk comes from sawdust far more than from finished boards, and it differs by species, because eastern red cedar is botanically a juniper. This guide covers which cedars carry which risk, what the research shows, and how to cut and sand cedar safely.

Is Cedar Toxic? The Short Answer

The honest answer is that it depends on the cedar and on how you meet it. The word “toxic” suggests something that poisons you by touch or by sitting near it, and the sources we checked do not describe that. They describe two narrower problems: irritation from fine dust and wood oils, and, for one species, true allergic sensitization.

If you are installing cedar siding, building a fence, or sitting on a cedar deck, you are not in the situation these studies measured. If you are ripping, planing or sanding cedar in a closed garage week after week, you are much closer to it. That split between living with cedar and making dust from cedar is the main thing most pages on this topic blur together.

Western Red Cedar vs Eastern Red Cedar: Different Trees, Different Risks

Two very different woods are sold as cedar in the United States. Western red cedar is the pale, straight-grained board used for siding, decking and outdoor furniture. Eastern red cedar, sold as aromatic red cedar, is the knotty, strongly scented wood used for closet lining and chests. The Wood Database notes that eastern red cedar is botanically a juniper (Juniperus virginiana) rather than a true cedar.

Wood	Botanical identity	Wood Database classification	Reported reactions
Western red cedar	Thuja plicata	Irritant and sensitizer	Runny nose, asthma, nervous system effects
Eastern red cedar (aromatic red cedar)	Juniperus virginiana, a juniper	Irritant only	Skin and respiratory irritation; severe reactions quite uncommon

Sources: Wood Database, western red cedar and Wood Database, eastern red cedar. Other woods sold as cedar, such as Spanish cedar, were not covered by the sources we read, so this page makes no claims about them.

The difference between an irritant and a sensitizer matters. An irritant bothers almost anyone given enough exposure and the effect fades when you stop. A sensitizer can teach your immune system to overreact, so reactions can become more severe with repeated exposure, even at lower doses than the first time.

Western Red Cedar Dust and Asthma: What the Research Shows

Western red cedar contains plicatic acid, a compound found only in this wood, and sensitization to it is the cause of western red cedar asthma. A 2012 study of former cedar workers states that between 4 and 13.5 percent of people working with this wood in an occupational setting develop asthma, and that it is the most common type of occupational asthma in southwestern Canada and the Pacific Northwest.

4 to 13.5% of occupationally exposed workers develop asthma from western red cedar. Source: PLOS ONE study of western red cedar asthmatics, 2012

The more striking finding is what happens afterward. In that study, 46 people removed from cedar exposure for an average of 14.8 years were tested, and about 63 percent still showed airway hyperresponsiveness. The authors write that most people with western red cedar asthma continue to have symptoms years after exposure ends. In plain terms, this is a condition you want to prevent, not one you can expect to leave behind by switching jobs.

Typical symptoms are cough, wheezing, chest tightness and shortness of breath. A useful warning sign from workplace safety guidance is a pattern: symptoms that get worse during work sessions and ease on days away from the dust. If you see that pattern after cedar projects, tell a doctor and mention the wood.

Exposure Limits for Cedar Dust, Side by Side

Exposure limits show how seriously the dust is taken. The figures below come from OSHA’s sawmill health-hazard page, which lists them together.

Standard	What it covers	Limit (8-hour average)
OSHA PEL	All wood dust, total dust	15 mg/m³ (5 mg/m³ respirable fraction)
NIOSH REL	All wood dust, total dust	1 mg/m³
ACGIH TLV	Western red cedar specifically	0.5 mg/m³

Put another way, the guideline for western red cedar is 30 times lower than the general OSHA wood dust limit, and half the general NIOSH figure, because of its asthma effects (see OSHA wood dust eTool). One caution: you may see 2.5 mg/m³ quoted online as an OSHA limit for western red cedar. That number comes from a 1989 rulemaking, and OSHA’s own wood dust page says the rule was remanded by a federal appeals court and its limits are not currently in force. Treat the ACGIH and NIOSH figures as guidance, not as a legal safe line.

How to Cut and Sand Cedar Safely

Occupational guidance puts engineering controls first and respirators second. For a home shop, that translates into the sequence below.

1. Capture dust at the tool: connect a dust collector or shop vacuum to your sander, saw or router rather than letting dust drift.
2. Ventilate: open the door and use a fan to push air out of the shop, not toward you or the house.
3. Wear a fitted respirator: use a NIOSH-approved N95 as a baseline for occasional work, seated tightly against the face.
4. Step up for frequent cedar work: if you sand or mill cedar often, move to a reusable half-mask respirator with particulate filters.
5. Keep dust off skin and clothes: wear a long-sleeve shirt, wash up after, and keep work clothes out of the living space.
6. Clean up carefully: vacuum fine dust instead of dry sweeping it back into the air.

Fit matters more than most people expect. The CDC’s NIOSH notes that an N95 filter is 95 percent efficient, but that certification is no guarantee a mask performs well as worn. It cites one study in which dust reduction averaged only 67 percent, and says disposable respirators are often much less effective than reusable half-masks (see the NIOSH guide to dust respirators). For a broader comparison of masks, see our guide to the best dust mask for woodworking.

Is Finished Cedar Safe to Live With?

Siding, fences, decks and furniture are made of the same wood, but the dust problem mostly disappears once the boards are cut and installed. We did not find a source that measured indoor air around finished cedar, so we cannot give a number. The practical advice is to take the dust seriously when you work the wood, and to treat strong cedar aroma in a small closed space as a possible irritant for sensitive people.

The Wood Database describes the scent of aromatic red cedar as coming from natural extractives that act as insect repellents, and says these can bother sensitive people. If cedar smell gives you a stuffy nose or headache, our pages on whether cedar can cause headaches and cedarwood oil diffusers cover the oil side in more detail.

If you are choosing cedar for a project and weighing it against other options, these guides help: which wood to use for outdoor furniture, cedar vs pressure treated for a fence, and what cedar costs. For what the wood is typically used for, see common uses for cedar wood.

Cedar Bedding for Hamsters and Other Small Pets

This is the other half of the question, and the evidence is thinner than the confident advice online suggests. A 1988 study in Comparative Medicine found that rats housed on cedar chips showed increases of 18, 46 and 49 percent in liver cytochrome P-450 content and two related enzyme activities. That shows cedar shavings change how a small animal’s liver works. It does not prove that a hamster on cedar will get sick.

Care sites commonly blame phenols and aromatic oils in cedar shavings for respiratory irritation, but the pages we read for this guide did not cite research of their own, so treat that mechanism as plausible rather than proven. The sensible, low-cost response is to choose paper-based bedding for hamsters, gerbils, mice and rats, and to ask your vet if an animal is already sneezing or wheezing on cedar.

Burning Cedar, Cedar Cutting Boards and Other Common Worries

Burning cedar and food contact are separate questions with their own pages. We cover smoke and fireplace use in what happens when you burn cedar, and food-contact use in whether cedar is good for cutting boards. If you finish cedar rather than leave it bare, oiling cedar wood and whether to paint cedar explain the options.

When to Talk to a Doctor

This page is general information, not medical advice. See a doctor if you develop cough, wheeze or chest tightness that tracks with cedar work, if symptoms linger after a project, or if you work with cedar regularly and have asthma already. Tell them which wood you handle and for how long. Early sensitization is easier to manage than the long-term pattern seen in the studies above.

Frequently Asked Questions

Is cedar toxic to humans?

Cedar is not a generally poisonous wood. The documented problems are irritation from dust and oils, and, for western red cedar, allergic sensitization that can lead to asthma in people who breathe the dust regularly. Finished cedar boards that you live with, such as siding or a fence, are not the same exposure as sawdust.

Is cedar dust harmful to breathe?

Yes, it can be. Wood dust in general irritates the eyes, nose and throat, and OSHA states that western red cedar dust has been shown to cause asthma. Wear a fitted respirator and use dust collection whenever you cut or sand cedar, and stop if you notice wheezing or chest tightness.

Is eastern red cedar toxic to humans?

Not in the way people fear. The Wood Database lists aromatic red cedar as an irritant only and says severe reactions are quite uncommon, though skin and respiratory irritation has been reported. It is botanically a juniper, so facts about western red cedar and plicatic acid should not be applied to it.

Can cedar make you sick if you just live with it?

The research this guide found measures workers exposed to cedar dust, not people living with finished cedar, so there is no firm answer from those sources. Sensitive people can react to the aroma or to dust from sanding and cutting. If a cedar closet or chest bothers you, that is a reason to ventilate it or stop using it.

Is cedar bedding safe for hamsters?

Most small-animal care guides advise against it. A 1988 study found that rats housed on cedar chips had higher liver enzyme activity than rats on other bedding. That is not proof of illness, but a paper-based bedding avoids the question entirely. Ask your vet about your specific pet.

Bottom Line

Cedar is not broadly toxic. Western red cedar dust is a real sensitizer with a documented asthma risk, aromatic red cedar is mostly an irritant, finished boards are a different exposure from sawdust, and cedar shavings are a questionable bedding choice for small pets. Control the dust, wear a properly fitted respirator, and the wood is easy to enjoy.