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EC number: 266-007-8 | CAS number: 65996-74-9 The oxidized surface of steel produced during reheating, conditioning, hot rolling, and hot forming operations. This substance is usually removed by process waters used for descaling, roll and material cooling, and other purposes. It is subsequently recovered by gravity separation techniques. Composed primarily of high-purity iron oxides. May contain varying amounts of other oxides, elements, and trace compounds.
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data

Acute Toxicity: inhalation
Administrative data
- Endpoint:
- acute toxicity: inhalation
- Type of information:
- migrated information: read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- weight of evidence
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: see 'Remark'
- Remarks:
- Mill scale is mainly and primarily composed of high-purity iron oxides (on average above 65%, i.e. FeO, Fe2O3, Fe3O4). Besides, other metal oxides and spinels, elements, and trace compounds such as oil residues <1% for all the uses except for batteries and Melting charge for which <3% can be found in the mill scale. More information on the justification of read across can be found in the attached document in the endpoint summarie of section 7.
Cross-referenceopen allclose all
- Reason / purpose for cross-reference:
- reference to same study
- Reason / purpose for cross-reference:
- reference to other study
Data source
Reference
- Reference Type:
- publication
- Title:
- Pneumotoxicity and pulmonary clearance of different welding fumes after intratracheal instillation in the rat.
- Author:
- Antonini JM, Murthy GGK, Rogers RA, Albert R, Uldrich GD, Brain JD.
- Bibliographic source:
- Toxicology and applied pharmacology, 140: 188-199.
- Report date:
- 1996
Materials and methods
Test guideline
- Qualifier:
- no guideline followed
- Principles of method if other than guideline:
- The study shows the effects of different welding fumes, which were instilled intratracheally, on parameters of lung toxicity. Iron(III)oxide is used as a negative control as it is considered as a relatively inert dust, and crystalline silica as a positive control. Only one dose was tested.
- GLP compliance:
- not specified
- Remarks:
- It is not customary to refer to GLP compliance in publications.
- Test type:
- other: intratracheal instillation
- Limit test:
- no
Test material
- Reference substance name:
- Diiron trioxide
- EC Number:
- 215-168-2
- EC Name:
- Diiron trioxide
- Cas Number:
- 1309-37-1
- Molecular formula:
- Fe2O3
- IUPAC Name:
- diiron trioxide
- Reference substance name:
- iron(III) oxide
- IUPAC Name:
- iron(III) oxide
- Details on test material:
- Name of test material (as cited in study report): iron oxide (γ- Fe2O3)
- Molecular formula (if other than submission substance): γ- Fe2O3
- Physical state: solid;particles of about 0.1-0.2 µm in diameter
- Other: magnetic iron particles (γ- Fe2O3) were produced by the combustion of Fe pentacarbonyl (Fe(CO)5) vapors as described by Vlberg and Brain (1979). The Fe(CO)5 is carried as a vapor to 650°C furnace, where air is added to provide oxygen for the formation of γ- Fe2O3. The reducing property of the H2 carrier gas is necessary to prevent oxidation of the Fe before it reaches the furnace, otherwise nonmagnetic hematite will result. The particles produced are crystalline in shape and measure about 0.1-0.2 µm in diameter. The final aerosol is produced from the rapid agglomeration of these individual units immediately after their formation in the furnace. The effluent is diluted with air and cooled to achieve the desired concentration and temperature.
Constituent 1
Constituent 2
Test animals
- Species:
- rat
- Strain:
- other: CD/VAF
- Sex:
- male
Administration / exposure
- Route of administration:
- other: intratracheal instillation
- Type of inhalation exposure:
- other: intratracheal instillation
- Vehicle:
- other: 150 µl of 0.9% sterile saline/100 g bw
- Analytical verification of test atmosphere concentrations:
- no
- Remarks:
- non relevant; intratracheal instillations
- Concentrations:
- Dose: 10 mg/kg bw particles instilled
- No. of animals per sex per dose:
- 4
- Control animals:
- other: Solvent control: saline; negative control: iron(III) oxide was used as a negative control because it is considered as a relatively inert dust; positive control: pneumotoxic crystalline silica,
Results and discussion
Effect levels
- Sex:
- male
- Dose descriptor:
- LC50
- Effect level:
- > 104 mg/m³ air
- Based on:
- test mat.
- Remarks on result:
- other: see details for this calculation below
Any other information on results incl. tables
Table 2a: Bronchoalveolar Lavage Cell Profiles (total number 10^6).
Time point |
Treatment |
Macrophage |
Neutrophil |
Lymphocyte |
1 day |
Iron(III) oxide |
3.8± 1 |
6.6± 0.7# |
0.3± 0.1# |
Solvent control |
5.1± 1 |
0.3± 0.1 |
0.1 |
|
Positive control |
5.7± 0.5 |
13.4± 1.8* |
0.6± 0.2# |
|
7 days |
Iron(III) oxide |
5.5± 0.8 |
1.6± 0.6# |
1.3± 0.3# |
Solvent control |
4.7± 0.6 |
0.1 |
0 |
|
Positive control |
7.2± 0.4 |
10.3± 0.6* |
0.7± 0.1 |
|
14 days |
Iron(III) oxide |
4.1± 0.3 |
1± 0.6 |
0.2± 0.1 |
Solvent control |
4.8± 0.2 |
0.2 |
0.2 |
|
Positive control |
6.8± 1.1 |
20.4± 1.4* |
1.6± 0.2* |
|
35 days |
Iron(III) oxide |
3.3± 0.5 |
0.2± 0.1 |
0.1 |
Solvent control |
3.7± 0.2 |
0.2± 0.1 |
0.1 |
|
Positive control |
8.7± 0.7* |
41.4± 5.2* |
2.8± 0.5* |
Values are means± SE, n=4
# significantly greater than saline control group (p<0.05); * significantly greater than all other groups
Results are presented in Table 2, Fig. 1, 2, 3 & 4 (see attachment below).
Iron(III) oxide
- Significant elevations were observed in the number of neutrophils and lymphocytes on days 1 and 7 postinstillation, in comparison to the solvent control.
- Albumine levels appearedincreased at the 1 day postinstillation measurement, while at the 14th day, there was no difference anymore in response in comparison to saline control group.
- LDH activity was significantly increased at day 1 postinstillation, whilst it diminished by 7 days and reached the same levels of control group by 14 days.
- None of the two cytokines was detected in the BAL fluid.
- Accumulation of the particles at some areas in the lungs was apparent at both (day 14 and 35) histopathological examinations, usually present inside the macrophages. At 35 day postinstillation lung changes from the Fe oxide were minimal. Macrophages containing oxide particle were observed in the terminal bronchioles and alveolar ducts.
Applicant's summary and conclusion
- Interpretation of results:
- other: In rats Fe2O3 behaves like an inert, non-toxic dust when instilled intratracheally at 10 mg/kg bw.
- Conclusions:
- In rats Fe2O3 behaves like an inert, non-toxic dust when instilled intratracheally at 10 mg/kg bw. No real evidence of pulmonary injury after exposure to the oxide particles was detected. The observed inflammatory responses were clearly associated with the particle clearance. After 14 days the lungs of the rats appeared fully recovered.
- Executive summary:
In an acute inhalation toxicity study groups of young adult male CD/VAF rats were exposed by intratracheal instillation to welding fumes. Iron(III) oxide was chosen as a negative control since it was considered by the investigators as a relatively inert dust and crystalline silica as a positive control. Iron(III) oxide particles were suspended in saline (one dose used, 1 mg suspended in 150 µl of 0.9% sterile saline/100 g bw). Animals then were observed for 14 days. No real evidence of pulmonary injury after exposure to the oxide particles occured. The observed inflammatory responses were clearly associated with particle clearance. Histopathology revealed that by 14 days the lungs of the rats appeared normal. Fe2O3 was indeed found to behave like an inert, non-toxic dust when instilled intratracheally at this dose level.An LC50 value for Fe2O3 was estimated by the conversion of the instilled dose to a concentration in air that was inhaled for 4 h by the rats; this resulted in a value > 104 mg/m3.
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