Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 231-130-8
CAS number: 7440-21-3
Based on the available data on
synthetic amorphous silica, silicon has low toxicological activity
after repeated oral exposure; even doses up to 2,500 mg/kg bw/day
(in rats) and 10,000 mg/kg bw/day (in mice) did not cause any
effects attributable to silicon in one chronic study with silica
gel. Because of the low toxicological activity of silicon ion
after ingestion, no oral DNEL is set. Also dermal DNEL is not
Although silicon is mainly handled in
the form of lumps, inhalable and respirable silicon may be formed
in some uses. Respirable dust is more important when considering
the lung or lower respiratory tract effects.
Based on a subchronic inhalation study in rats, silicon particles
in the respiratory size range (MMAD 2.6 µm) caused only very mild,
local inflammatory effects in the lungs of the exposed animals. On
the basis of the outcome of that study, a DNEL-value of 0.3
mg/m3 was derived for worker exposure to respirable
For the inhalable fraction of silicon there is no
substance specific data available in relation to adverse effects
after repeated exposure. However, it is relevant to set a
long-term inhalation DNEL for workers also for that fraction. For inhalable
silicon it is thus justified to follow the currently lowest
occupational exposure limit value for inert dust (poorly soluble
inert particles) in Europe, which is the German value (DFG 1997,
2014) of 4 mg/m3.
The recent epidemiological data from
the silicon/ferrosilicon manufacturing have shown only effects
attributable to general dust exposure. It has been shown in
different industries that dust exposure may increase the risk of
chronic bronchitis or COPD. In the recent study in Norwegian
ferroalloy industry (Johnsen et al. 2010), an annual additional
decline in lung function resembling the decline caused by smoking
(6.4 ml fora non-smoking
employee of average heightestimated
on the basis of linear mixed effects model) was suggested at
median exposure level of 2.3 mg/m3of general dust
(representing thoracic fraction).This
is close to the current view that occupational exposure to dust in
general results in an extra decline in FEV1 of 7 to 8
ml/year (Toren and Balmes, 2007). For an exposure level of 1 mg/m3
Johnsen and co-workers (2010) calculated an additional
decline of 2.7 ml for non-smokers. However, when the absolute
annual decline in FEV1was examined by exposure groups
(tertiles of exposure level: <1, 1.1 to 3.0 and >3.1 mg/m3)
and controlled by age the values at the two lowest exposure group
were close to the predicted, physiological annual decline of FEV1.
Thus, this study suggests that 1 mg/m3 (thoracic
fraction) can be regarded as a NOAEChumanfor the
effects of dust exposure at FeSi/Si industry.According
to the data from 7 of these FeSi/Si plants, the median levels of respirable
dust in this industry varied between 0.4-2.1 mg/m3 (Elkem
2005), being highest at furnace department. Median levels of
respirable amorphous silica (representing silica fume) were
~0.1-1.3 mg/m3. No signs of fibrosis in workers were
seen in these studies. However, since silicon particles are only a
minor component of these dusts present in silicon/ferrosilicon
factories no firm conclusions on the inhalation toxicity and
dose-response of silicon can be made.
of the low toxicological activity of silicon ion after ingestion,
no oral DNEL is set. Also dermal DNEL is not considered relevant.
For inhalation, the DNEL for respirable silicon is set at 0.3
mg/m3, and for inhalable silicon set at 4 mg/m3.
A detailed justification paper discussing the interpretation of
the 90-day inhalation study results and DNEL derivation is
attached in Section 13 of the Iuclid dossier.
As there is no consumer exposure to metallurgical silicon, no DNEL
for the general public is derived.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
Welcome to the ECHA website. This site is not fully supported in Internet Explorer 7 (and earlier versions). Please upgrade your Internet Explorer to a newer version.
Do not show this message again