This is for when people ask about wood bedding hazards. Pine pellet litter has typically has the volatile components removed, but wood stove pellets (which some people have used in the past do not and actually contain some woods which are even more associated with carcinogenic effects). http://onlinelibrary.wiley.com/doi/10.1002/ajim.4700240511/abstract Carcinogenic effects of wood dust: Review and discussion - Leena A. Nylander MS1,*, - John M. Dement PhD, CIH2,â Article first published online: 19 JAN 2007 DOI: 10.1002/ajim.4700240511 Copyright é 1993 Wiley Periodicals, Inc., A Wiley Company Issue American Journal of Industrial Medicine Volume 24, Issue 5, pages 619--647, November 1993 Keywords: - wood dust; - occupational exposure; - furniture workers; - carpenters; - nasal cancer; - occupational disease; - toxicity; - mutagenicity; - prevention Abstract Occupational exposure to wood dust (alone or chemically treated) is associated with an increased risk of developing adenocarcinoma of the nasal cavity. The specific causative agents, i.e., wood dust alone (natural products), wood dust with additives used in the processing or manufacturing of wood products, and/or physical determinants of wood dust and the associated risk factors, are not known or understood. The strongest association of exposure to wood dust and development of nasal cancer is observed in those occupations where workers are exposed to hard wood dust and chemical additives are not used. The time between first occupational exposure to wood dust and the development of adenocarcinoma of the nasal cavity averages 40 years (range 7--70 years). The epidemiological data available are not sufficient to make a definitive assessment between wood dust exposure and increased risk for cancer other than nasal cancer. The toxicity, mutagenicity, and carcinogenicity of wood dust to laboratory animals or in vitro with animal or microbial cells have not been throughly studied. Thus there is no direct experimental evidence on the potential hazards of wood dust. Data are insufficient or lacking on 1) wood dust exposure levels in ambient air and worker's breathing zone, and the deposition in the nasal cavity; 2) hard vs. soft wood dusts; 3) particle size and shape; 4) chemical composition of wood dust and the extent of contamination with chemical additives; and 5) interaction between inhaled wood dust, chronic irritation, and tobacco smoking. These data are required so that one can understand the association between wood dust exposure and nasal cavity tumors, along with demographic differences in cancer rates, and to develop strategies for intervention and reduction of disease causing agents in order to reduce risk to wood industry workers. (c)1993 Wiley-Liss, Inc. Here is a grad student compilation paper has useful info: http://www.trifl.org/cedar.shtml That link above is a meta-paper up to the mid 1990s with many references. These PubMed abstracts may also be of interest; I I know that oak and beech have not been publicly mentioned in ferret discussions in relation to carcinogenic aspects: http://www.ncbi.nlm.nih.gov/pubmed/8231799 (abstract below) http://www.ncbi.nlm.nih.gov/pubmed/189039 (abstract below) Med Pr. 1993;44(3):277-88. [Biological effect of wood dust]. [Article in Polish] Maciejewska A, Wojtczak J, Bielichowska-Cybula G, Domanska A, Dutkiewicz J, Motocznik A. Source Zaktadu Aerozoli Instytutu Medycyny Pracy, Lodzi. Abstract The biological effect of exposure to wood dust depends on its composition and the content of microorganisms which are an inherent element of the dust. The irritant and allergic effects of wood dust have been recognised for a long time. The allergic effect is caused by the wood dust of subtropical trees, e.g. western red cedar (Thuja plicata), redwood (Sequoia sempervirens), obeche (Triplochiton scleroxylon), cocabolla (Dalbergia retusa) and others. Trees growing in the European climate such as: larch (Larix), walnut (Juglans regia), oak (Quercus), beech (Fagus), pine (Pinus) cause a little less pronounced allergic effect. Occupational exposure to irritative or allergic wood dust may lead to bronchial asthma, rhinitis, alveolitis allergica, DDTS (Organic dust toxic syndrome), bronchitis, allergic dermatitis, conjunctivitis. An increased risk of adenocarcinoma of the sinonasal cavity is an important and serious problem associated with occupational exposure to wood dust. Adenocarcinoma constitutes about half of the total number of cancers induced by wood dust. An increased incidence of the squamous cell cancers can also be observed. The highest risk of cancer applies to workers of the furniture industry, particularly those dealing with machine wood processing, cabinet making and carpentry. The cancer of the upper respiratory tract develops after exposure to many kinds of wood dust. However, the wood dust of oak and beech seems to be most carcinogenic. It is assumed that exposure to wood dust can cause an increased incidence of other cancers, especially lung cancer and Hodgkin's disease. The adverse effects of microorganisms, mainly mould fungi and their metabolic products are manifested by alveolitis allergica and ODTS. These microorganisms can induce aspergillomycosis, bronchial asthma, rhinitis and allergic dermatitis. PMID: 8231799 [PubMed - indexed for MEDLINE] J Natl Cancer Inst. 1977 Jan;58(1):149-50. Possible carcinogenic effects of cedar shavings in bedding of C3H-Avy fB mice. Vlahakis G. Abstract C3H-AvyfB female mice were tested on bedding consisting only of low-resin pine and on bedding ofpine plus cedar shavings. Tumor occurrences were similar in both groups of animals, with a slightly lower incidence and slightly higher average age for mammary gland tumors in the females on bedding of pine plus cedar. From these results, the high incidence of cancer in the C3H-AvyfB strain could not be attributed to the routine use of cedar shavings in the bedding material. PMID: 189039 [PubMed - indexed for MEDLINE] (2010, Steve Crandall) [Posted in FML 7351]