Media Release - Commonly used toilet deodorant
chemical not a concern
03 Aug 2000
The National Industrial Chemicals Notification and Assessment Scheme
(NICNAS) released for public comment today a draft report on the
hazardous industrial chemical, para-dichlorobenzene. The report
concludes that the use of the chemical is well controlled at present and
unlikely to cause any harm to people or the environment in Australia.
Para-dichlorobenzene is widely used as a deodorant in public toilet
facilities, including those in schools. The chemical is also available
to the public for use in homes were it is used as a toilet deodorant, an
air freshener and to protect clothes from damage due to moths and
Total annual imports of the chemical into Australia amount to between
five hundred and one thousand tonnes, most of which is imported by three
companies. The chemical is processed into small blocks or disks prior to
packageing for distribution to commercial cleaning suppliers or
retailers to the public. The chemical is volatile and works by producing
a vapour that masks odours. At high concentrations the vapour may cause
irritation to the eyes and nose of some individuals. The handling and
processing of para-dichlorobenzene was found not to constitute a risk to
those employed in the industry. Concerns that the chemical, an
organochlorine, may produce cancer in humans were investigated but,
after careful evaluation of the data available, were found to be
Para-dichlorobenzene is widely available to the public through
supermarkets and general stores. Products containing the chemical are
typically greater than 90% para-dichlorobenzene. The NICNAS assessment
found that, when used according to the instructions on the package, the
chemical should not constitute a risk to the public.
Although para-dichlorobenzene is released to the environment, it is
broken down quickly and is not expected to cause harm to living
The contact at NICNAS for free copies of the draft report and public
submissions is Dr Michael Muller on phone (02) 9577 9473 or email
mullerm@ASCC.gov.au. Submissions must be received within the next 28
MEDIA: For further information please contact Nick Miller,
Communications Manager, NICNAS, on (02) 9577 9349.
Para-Dichlorobenzene: Draft Report for Public Comment - Summary
Para-dichlorobenzene was declared a Priority Existing Chemical on the 7
April 1998. The declaration of para-dichlorobenzene was in response to
concerns relating to possible human health risks and environmental
hazards associated with the widespread use of the material in school and
public toilet facilities and as a domestic air freshener.
Import and use
Up to 1000 tonnes of para-dichlorobenzene are imported and used annually
in Australia. Para-dichlorobenzene is primarily used as a deodoriser in
public toilet facilities, in household toilets and as a room freshener
in addition to some minor uses in the agricultural and pharmaceutical
Para-dichlorobenzene is readily adsorbed by inhalation and oral routes
and less well by dermal contact. Target organs for para-dichlorobenzene
are adipose tissue, liver, kidneys and lungs. The parent compound and
its metabolites are rapidly excreted in the urine. There is no evidence
that para-dichlorobenzene bioaccumulates in tissues.
Acute exposure to para-dichlorobenzene vapour within the range of 30 to
60 ppm in air is associated with irritation to the nose, eyes and upper
respiratory tract. Exposure to vapour of 80 to 160 ppm results in acute
discomfort, painful irritation of the nose and eyes and may induce
breathing difficulties. Ingestion of large doses of para-dichlorobenzene
have been associated with vomiting, vertigo, disorientation, tiredness,
oedema and conversion of haemoglobin to methemoglobin. Chronic exposure
to high doses of para-dichlorobenzene may result in headache, nausea,
vertigo, ataxia, dysarthria, hyporeflexia, paresthesia, behavioural and
haematological changes including anaemia.
Genotoxicity studies of para-dichlorobenzene have produced negative
results. However, para-dichlorobenzene does induce the formation of
kidney tumours in male rats and liver tumours in both sexes of mice
after prolonged exposure. The formation of kidney tumours in male rats
is thought to be due to the presence of the protein, a2m-globulin. As
a2m-globulin is specific to the mature male rat, para-dichlorobenzene is
not considered to present a carcinogenic risk to humans by this
mechanism. The tumours observed in mice after prolonged exposure to para-dichlorobenzene
are also considered to be irrelevant to humans. There are significant
differences in the metabolism of para-dichlorobenzene in the liver of
mice and humans and it has been further observed that the mouse strains
used demonstrate a high natural rate for liver tumour formation.
Exposure of pregnant rats to para-dichlorobenzene vapour produced no
evidence of maternal toxicity or embryo-, foeto- or teratogenicity.
Occupational health and safety
The occupational risk assessment for para-dichlorobenzene concluded
that, for known Australian work situations, potential atmospheric
concentrations of para-dichlorobenzene are unlikely to reach levels
likely to cause acute effects, including eye or respiratory irritation.
In addition, it is unlikely that workers in these occupations will be at
risk from chronic adverse health effects related to para-dichlorobenzene
exposure, as margins of exposure are generally high for inhalation
exposure. In the absence of any monitoring data for workers involved in
the hygiene sector estimates for para-dichlorobenzene exposure were
obtained using the known physical properties of the chemical and
computer modelling. Results from this modelling indicate that the risk
to workers is expected to be low.
Public exposure will principally arise from the use of
para?dichlorobenzene in toilet deodorant blocks and air fresheners.
Public exposure will occur principally by inhalation, with the potential
for dermal exposure reduced by the containment of para-dichlorobenzene
in cellophane wrapping during handling. There have been no confirmed
reports of skin irritation or sensitisation in widespread human use.
Consequently the risk of dermal irritation or sensitisation is
considered to be low.
Investigations of the airborne concentrations resulting from the use of
para-dichlorobenzene as a household air freshener or as an insect
repellent in wardrobes indicate that concentrations are likely to be
well below those where irritation or chronic effects may be observed.
The risk to the public from the intended use of para?dichlorobenzene in
the household or public toilets is considered to be low.
Environmental exposure to para-dichlorobenzene can occur due to the use
of the product in toilets from which it may be washed into the sewer
system or enter the atmosphere by virtue of its volatile nature.
Para-dichlorobenzene does not persist in air or surface water but
accumulates in anaerobic sediments. Para-dichlorobenzene has a medium
acute toxicity for aquatic life and may impair the reproduction of
aquatic life. However, based on current patterns of para-dichlorobenzene
use within Australia, the risk to the environment is expected to be low.
Recommendations for reducing potential occupational health and safety
risks for para-dichlorobenzene include the monitoring of airborne para-dichlorobenzene
to be undertaken and a review of the current occupational exposure
standard for para-dichlorobenzene by the National Occupational Health
and Safety Commission.
The hazard classification should be amended to include the follows
safety phrases, S23 (Do not breath vapour), S24 (Avoid contact with
skin), S25 (Avoid contact with eyes) and S51 (Use only in well
The National Industrial Chemicals Notification and Assessment Scheme
(NICNAS) operates under the Commonwealth Industrial Chemicals
(Notification and Assessment) Act 1989.
NICNAS is a statutory scheme within the portfolio of the Minister for
Health and Ageing. Its approach to the scientific assessment of
chemicals covers toxicity, exposure and use to assess the environmental,
public health and occupational health and safety risk. For more
information see the web site
Nick Miller, NICNAS, (02) 8577 8810 or 0407 228 285