1.2.4.1 Nasal Cancer
The association between nasal cancer and occupational exposure to wood
dust, especially in the furniture industry, was first noted in the late 1960’s in the
UK (Macbeth, 1965; Acheson, 1976), where the annual incidence of nasal
adenocarcinoma was 0.7 cases per 1000 and is estimated as 500 times the
level found in the general population (Acheson et al., 1968). Nasal cancer is a
significant hazard of woodworking, particularly associated with furniture making
and hardwoods (Acheson et al., 1981; Rang and Acheson, 1981). Australian
studies have confirmed that not only furniture workers but also sawmillers and
carpenters are at risk (Ironside and Matthews, 1975; Franklin, 1982). Hardwood
dust exposure has been shown to be associated with nasal adenocarcinoma
(Acheson et al., 1981) while softwood dust exposure has been shown to
increase the risk of both sinonasal and nasopharyngeal squamous cell cancers
(Voss et al., 1985; Vaughan and Davis, 1991). The aetiological factors for
nasal adenocarcinoma are still unknown. A review has stated that it is possible
that the health hazards of hardwoods are related more to physical properties
than to any chemical constituents (Walker, 1988). The period of latency on
average for nasal cancer is about 41 years (Andersen et al., 1977). The
International Agency of Research on Cancer (IARC) in their monograph on the
“Evaluation of Carcinogenic Risks to Humans”, has concluded that wood dust is
The carcinogenic aspects of exposure to wood dust have been reviewed by
Wills (1982), HSE (1986), Walker (1988), Nylander and Dement (1993), and in
more detail in an IARC monograph, 1995.
The association between nasal cancer and wood dust exposure has been
confirmed to varying degrees in France (Luce et al., 1993; Leclerc et al., 1994);
the Netherlands (Hayes et al., 1986); a pooled case-control study of seven
countries - France, China, Germany, Italy, the Netherlands, Sweden, the US
(Demers et al., 1995); Australia (Ironside and Matthews, 1975; Franklin, 1982),
the United Kingdom (Macbeth, 1965; Acheson et al., 1981); Denmark, Finland
and Sweden (Hernberg et al., 1983a; 1983b), British Colombia (Elwood, 1981),
Japan (Fukuda and Shibata, 1988), and Norway (Voss et al., 1985). The
studies reported from the US are less convincing (Imbus and Dyson, 1987;
Viren and Imbus 1989). These two studies have shown that there was no
overall excess of deaths from nasal cancer in wood-related industries including
furniture manufacturing in the US.
The size-selective sampling of wood dust in US furniture plants has shown that
85-90% of the dust by weight is >15µm aerodynamic diameter (Whitehead et
al., 1981b). Whereas a UK study (Hounam and William, 1974) found only 30-
40% wood dust in furniture plants to be >13.7µm aerodynamic diameter. A
Danish furniture study found only 15% of the dust to be 15µm in size
(Anderson et al., 1977). The three European studies indicated that the airborne
dust particle sizes found in European furniture plants were finer compared with
adenocarcinoma observed among furniture workers in European countries
compared with the US. Larger wood dust particles are not retained in the nose,
since the deposited larger particles are removed by mucociliary clearance.
Only the finer particles are trapped in nasal passages, causing mucostasis,
which may in turn lead to nasal cancer.
It has been reported that the much lower risk observed in British Colombia
compared with English furniture makers is most probably due to the use of
softwood rather than hardwood, or the use of coarse and unseasoned timber
rather than kiln dried timber, or the use of rough sawing rather than fine
finishing, or outdoor or large indoor workplaces rather than small shops or a
combination of these factors. The study also reported that in British Colombia,
forestry and sawmills employ a large proportion of the population while furniture
manufacturing is very limited. Workers performing sanding operations may
have an especially high risk of development of cancers within the sinonasal
area because the mean airborne wood dust concentration in the breathing zone
of workers engaged in hand or machine sanding has been found to be nearly
three times the concentration found in the breathing zone of persons employed
in sawing, planing and drilling (Anderson et al., 1977; Wills, 1982).
Excess risk of nasal cancer is associated with high levels of exposure to
airborne wood dust. One review has suggested that nasal adenocarcinoma can
be eliminated in Europe and it’s occurrence can be prevented in the US if wood
dust exposures do not exceed an 8 hr time-weighted-average (TWA) of 5
1.2.4.2 Nasal Adenocarcinoma Reported from Australia
Nasal adenocarcinoma among woodworkers has been reported from Tasmania
(Franklin, 1982) and Victoria (Ironside and Matthews, 1975). Both studies have
stated that males are at a greater risk than females and occupation as the
possible factor for the difference. The annual incidence of nasal cancer is 5 per
million per annum for Tasmania (Franklin, 1982) and 7 per million per annum
for South Australia (Pisaniello and Muriale, 1990), incidences which are similar
to the annual incidence of 7-10 per million in the UK. The proportion of nasal
adenocarcinoma to total nasal cancer was 20% in Victoria, and 65% in
Tasmania whereas in High Wycombe (UK) the proportion was 25% (Franklin,
1982). In South Australia, the proportion is 20%, similar to Victoria. The
relatively greater risk found in Tasmania may be due to the more extensive use
of hardwoods, especially blackwood (Acacia melanoxylon) (Pisaniello and
Muriale, 1990). In Tasmania, blackwood is the most common wood (65% of
total solid wood) processed among furniture manufacturing companies
(Ozarska, 1988). The British studies reported that only furniture workers were
at a greater risk of nasal adenocarcinoma (Acheson et al., 1981). The
Tasmanian and Victorian studies confirmed that not only furniture workers but
also all woodworkers including sawmillers and carpenters are at risk. The
possible reasons given are, different varieties of timber processed; the drier
wood processed by Australian sawmillers and carpenters (because of climate
or treatment of timber) compared with their English counterparts; and
furniture industry is the larger industry in the UK (Ironside and Matthews,
1975).
1.2.4.3 Other Types of Cancers
A variety of cancers have been described: increased risks of Hodgkins disease
among woodworkers (Milham and Hesser, 1967); non-Hodgkins lymphoma
among furniture workers (Miller et al., 1989); leukaemia among furniture
makers (Miller et al., 1989) and sawmillers (Jappinen et al., 1989);
nasopharyngeal cancer among foresters and loggers (Kawachi et al., 1989),
furniture makers (Moulds and Bakowski, 1976), and sawmillers (Hardell et al.,
1982); lung cancer among sawmillers (Kawachi et al., 1989), plywood workers
(Kauppinen et al., 1993), carpenters (Robinson et al., 1996); liver cancer
among sawmillers (Kawachi et al., 1989), stomach cancer among carpenters
(Robinson et al, 1996); skin cancer among sawmillers (Jappinen et al., 1989);
lip cancer among carpenters (Kawachi et al., 1989) and sawmillers (Jappinen
et al., 1989); mouth and pharynx cancer among sawmillers (Jappinen et al.,
1989) and male breast cancer and malignant mesothelioma among carpenters
(Robinson et al., 1996). Some of these studies reported that the possible risk
factors included; wood dust, terpenes, organic solvents, chemical
preservatives, and fungicides used during wood processing. A Swedish study
has reported an increased risk of lung cancer, malignant mesothelioma and
malignant lymphoma among pulp and paper mill workers, and has suggested
that exposure to fresh wood is the probable risk factor (Toren et al., 1996).