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EC number: 294-409-3
CAS number: 91722-09-7
Substance formed during processing of liquid steel or during production of iron castings. Consists primarily of fused silicates and trace elements as oxides as well as trace of alloying elements.
No indication for reproductive/developmental toxicity, based on negative
test results from available in vitro and in vivo mutagenicity studies.
No harmonised classification for reproductive/developmental toxicity for
the components of the slags.
mutation in bacteria/mammalian/ and cytogenicity or micronucleus
formation refers to the ability of a substance to change and/or disrupt
the genetic material (DNA) of bacteria/mammals/mammalian cells. If
there is a positive result, the substance may cause gene mutagen in
bacteria, mammals, cytogenicity or formation in mammalian cells of a
micronucleus. It may also impact the genetic material in humans which in
turn could lead to the development of cancer, affect reproduction or
lead to an adverse health effect in offspring.
there is a positive result in one or more in vitro tests, further
mutagenicity studies in vivo must be considered to assess these
types of effects, the possible concern for effects in humans needs to be
further assessed in a living animal test system.In vivomutagenicity
refers to the ability of a substance to damage the genetic material
(DNA) of living mammals.
reproductive and/or developmental toxic substance may affect fertility
and can cause health effects in offspring after recurring contact.
The exposure can occur by ingestion, inhalation, or skin contact.
a substance is a reproductive and/or developmental toxicant, it may
induce fertility problems, problems with the ability to reproduce and
serious health effects in the offspring. A screening test for
reproduction/developmental toxicity gives a first impression of possible
problems with the ability to reproduce.
available test results from following studies (in
vitro and in vivo) are all negative:
The negative test results
indicate there are no potential to induce damages/changes in the genetic
material (DNA) of living mammals.
The exposures by
ingestion and skin contact are considered as negligible (see further
information in endpoint 7.2 and 7.3) and are not critical and/or
relevant for this endpoint.
The exposure by
inhalation was assessed as not acute toxic, supported by the test
results from performed acute and short-term repeated inhalations
Based on previous scientific considerations, no
further testing for screening test for reproduction/developmental
toxicity is required.
For further discussion, summary and test result for each endpoint below,
kindly see the link (linked study/endpoint records) in Cross reference
under Administrative data
Acute toxicity (oral, dermal and inhalation)
No acute toxicity of any routes, based on the conclusion of the
following test results:
Oral: ABS, GBS, EAF C: OECD TG 401, rats: LD50 > 2000 mg/kg bw, BOS,
SMS: OECD TG 423, rats: LD50 > 2000 mg/kg bw.
Inhalation: GGBS: OECD 403, rats: 4 h-LC50 >5235 mg/m³
Skin: BOS, SMS: rats OECD 402, rats: LD50 > 4000 mg/kg
Additional information (ABS): equal to oral intake. Slag leachtest
fulfil the quality criteria of the German Federal Drinking Water
Regulation. Conclusion: pose no risk to human health, when the criteria
for drinking water is fullfil.
Several in vitro and in vivo tests on ferrous slags demonstrate that
these slags have no irritant and no corrosive potential to skin and eye.
From dermal toxicity testing with BOS and SMS, it is concluded, that no
components of these UVCBs are taken up at relevant concentrations
through the skin. Therefore this absorption of ferrous slag through the
skin can be neglected including toxicokinetics.
ABS, EAF C, and EAF S are not sensitising when tested according to OECD
406 and NF EN ISO 10993-10 (February 2003) concerning biological
evaluation of medical devices: Tests for irritation and delayed-type
hypersensitivity. BOS and SMS are not sensitising when tested according
to OECD TG 406 Skin Sensitisation Test.
There is no indication of carcinogenic potential of ferrous slags based
on available data from literature.
Ferrous slags do not have any mutagenic potential and/or change/disrupt
the DNA of bacteria and mammalian cells, assessed by the negative test
results, performed by OECD 471, OECD 474 and OECD 476.
Ferrous slags are solid UVCB substances (substances of Unknown or
Variable composition, Complex reaction products or Biological materials)
that resemble natural rocks found in terrestrial and sediment systems.
The physicochemical properties are almost identical among ferrous slags,
and their benign toxicological and ecotoxicological profiles are very
similar. Similarities comprise also the mineralogical composition of the
ferrous slags. Importantly, all mineral components of ferrous slags are
present in natural rocks; no new component is introduced during steel
processing. Ferrous slags demonstrate low extractability in water as
metals in slag were found to be generally resistant to leaching. Ferrous
slags are virtually free of hazardous fibres. Overall, ferrous slags can
be considered artificial volcanic rocks.
The ‘Ferrous Slag Category’ comprises the following 5 slag types:
(1) ABS/GBS i.e., Slag, ferrous metal, blast furnace (air cooled or
(2) BOS i.e., Slag, steelmaking, converter (converter slag),
(3) EAF C i.e., Slag, steelmaking, elec. furnace (carbon steel
(4) EAF S i.e., Slag, steelmaking, elec. furnace (stainless/high alloy
steel production), and
(5) SMS i.e., Slag, steelmaking. No significant hazard to environmental
and ecological receptors has been anticipated for these slags.
The pathways of exposure quantitatively evaluated in this assessment
were inhalation of suspended airborne ferrous slag particulates,
incidental ingestion of ferrous slag, and dermal contact with ferrous
From single-dose toxicity testing in animals via the oral, dermal and
inhalation routes it can be concluded that ferrous slags are not acutely
toxic. They do not need to be classified as oral, dermal and inhalation
toxicants; neither a signal word nor hazard statement is required.
Furthermore, ferrous slags exhibit no relevant irritant or sensitising
potential, and does not show any mutagenic potential. Extensive testing
in rat inhalation studies revealed that the biological responses to
inhaled ferrous slag show no correlation to the course of pulmonary
toxicity reported for amorphous silica (quartz); quartz dust served as
positive control as it is well known to produce irreversible lung
damage. Overall, ferrous slag in vivo data differ markedly from those
reported for quartz in rats exposed at similar doses.
Supplemental in vitro testing also shows that ferrous slags, alike
natural mineral samples, do not cause significant toxicity in cultured
alveolar macrophages, nor does the slags induce major reactive oxygen
species (ROS) formation and oxidative stress or trigger any inflammation
in a biological system. On the contrary, the positive assay control
quartz caused consistently evidence for an inflammation response in
vitro associated with a significant secretion of the mature forms of
pro-inflammatory cytokines from the cells, strong activation of the
inflammasome pathway, and impaired phagocytosis functionality of
Taken together the data generated in vivo and in vitro for ferrous slags
it can be summarised that ferrous slags behave like natural rock,
representing a rather inert category of UVCB substances. As expected
biokinetics investigations in rats following inhalation exposure to high
concentrations of ferrous slag particulates showed
concentration-dependent lung burdens of persistent metals after
inhalation exposure of rats to ferrous slags but there was no
translocation to other organs of any metal investigated. The animal data
suggest that the rat lung was able to get rid of the inhaled solid
aerosol via physiological clearance mechanisms.
The toxicology programme for ferrous slags, as documented in the
Chemical Safety Report (CSR) as part of the registration dossier of
ferrous slags (CSR 2017), can be considered to fulfil the
information requirements for REACH (Registration, Evaluation,
Authorisation and Restriction of Chemical substances) registration at
the European Chemicals Agency (ECHA). There is sufficient, adequate and
reliable information on hazardous properties for classification and risk
assessment of ferrous slags.
The registrant makes use of Annex XI criteria regarding the scientific
necessity of information, the technical possibility for testing, and
exposure-based waiving to adapt the standard information requirements
under REACH. Data waiving is justified for repeated oral dose toxicity
testing and studies for toxicity to reproduction or developmental
toxicity / teratogenicity in order to avoid unnecessary testing in
vertebrate animals. These non-clinical studies are waived based on
physico-chemical properties of ferrous slags that resemble natural
rocks, mimicking the natural concentration of an element in the
environment, and the low solubility in water, low extractability of
components from ferrous slags, and lack of toxicological bioavailable
fraction / systemic bioavailability of metals. Slag has been utilised in
road construction for more than two centuries and wealth of humane
experiences are available. Furthermore, ferrous slags have no PBT
(persistent, bioaccumulative and toxic) or vPvB (very persistent and
very bioaccumulative) properties. It is also of note that no toxicity
effects of particular concern were observed in animal inhalation studies
that is the likely route of human exposure, and results obtained from
suitable in vitro studies demonstrate no certain dangerous property of
ferrous slags. Finally, previous risk assessments of slags provide
sufficient supporting evidence that toxicity can reliably be excluded.
Short description of key information:
No evidence from acute tests or other data for any reproductive
effect. No data available from studies dedicated especially to
reproduction toxicity. As slags are similar to natural rock, no
reporductive effects have to be expected.
No evidence from acute tests or other data for developmental toxicity or teratogenicity.
See endpoints 7.8.1 for further discussion and summary.
The physico-chemical properties of ferrous slags are low solubility in
water, low extractability of components from ferrous slags, and lack of
toxicological bioavailable fraction/systemic bioavailability of metals.
Furthermore, ferrous slags have no PBT (persistent, bioaccumulative and
toxic) or vPvB (very persistent and very bioaccumulative) properties.
I the likely route of human exposure is inhalation and there is no
toxicity effects of particular concern observed in animal inhalation
studies, and results obtained from suitable in vitro studies demonstrate
no certain dangerous property of ferrous slags.
Finally, previous risk assessments of slags provide sufficient
supporting evidence that reproduction and developmental toxicity can
reliably be excluded.
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.
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