Chromium(VI) compounds pose a considerable health risk in many areas of work. This is particularly true when employees have to handle products containing chromate without adequate
Properties and risks of chromium(VI)
Chromates (chromium(VI) compounds) are hazardous substances. The starting material for their formation is sodium dichromate, a chromium(VI) salt obtained from chromium ore. Chromates are classified as carcinogenic according to category 1B (H350), with the exception of barium chromate. In addition, chromium(VI) compounds can also have a sensitizing effect on the skin and respiratory tract in the event of direct contact. The health risks arise primarily when handling chromate-containing substances or contaminated surfaces, for example by inhaling chromate-contaminated dusts or through skin contact.
Work areas with chromate exposure
People in the following areas are particularly at risk:
- Digestion and processing of chrome ores
- Production of hexavalent chromium compounds
- Alloys
- Welding and grinding of sheet metal with chromium-containing coatings or stainless steel
- Pickling and cleaning metals
- Bright and hard chrome plating with chromium(VI) oxide as the starting material
- Dealing with thermal insulation and older night storage heaters
- Areas of thermally influenced chrome-alloyed industrial components such as steam pressure pipes, turbines and chrome-alloyed steel pipes
- Thermally conductive plant components with alkali and alkaline earth metal-containing insulating materials such as in coal-fired power plants, gas and biomass power plants, combined heat and power plants, heating plants, wood chip power plants, waste incineration plants and chemical industrial plants
- Maintenance work on power plants or combined heat and power plants with release of calcium chromate
- Use of chromium(VI) oxide and alkali chromates in various industries
- Spray painting with corrosion protection agents containing chromium
Formation of toxic chromium(VI) compounds
Studies and practical evidence show that chromium(VI) compounds can be formed under the following conditions:
- Steel temperatures in the range from 350 °C to 800 °C.
- Chromium-containing steels, especially high-alloy variants in turbines, media lines, gas turbines or steam turbines, industrial furnaces, emergency power generators, bolts and screws
- Alkali and alkaline earth metal oxides (e.g. calcium oxide, magnesium oxide) from insulating materials and assembly pastes
- Humidity and atmospheric oxygen in the vicinity of steel surfaces
- Water vapor from 550 °C
The alkali and alkaline earth metals used in the materials can develop different chromium(VI) compounds. These reactions often lead to yellowish deposits on steel or adjacent materials.
Health risks from chromium(VI) compounds
Chromates can cause severe allergies and eczema on contact with the skin and form so-called “chromate ulcers“. Inhalation of chromium(VI) can cause irritations such as coughing, sneezing, asthma and chronic bronchitis. Long-term exposure can also lead to serious illnesses such as lung, nose and sinus cancer.
Amended Hazardous Substances Ordinance 2024 – traffic light model
Hazardous Substances Ordinance 2024: The traffic light model
With the amendment of the Hazardous Substances Ordinance on December 5, 2024, new protective measures were introduced for activities involving carcinogenic hazardous substances such as chromates (chromium(VI) compounds). The familiar concept of measures from TRGS 910, the so-called
- Green: low risk up to the acceptance concentration (AK)
- Yellow: medium risk up to the tolerance concentration (TC)
- Red: high risk if the occupational limit value is exceeded
With this classification, the possible hazards can be better assessed and the urgency of measures can be more clearly determined. In the case of carcinogenic hazardous substances such as chromate, appropriate protective measures can be introduced once the risk level has been assigned. They are adapted, for example, according to the exposure level, if an occupational limit value is exceeded or to achieve a reduced exposure level.
According to §10 of the amended ordinance, special protective measures are required for activities involving category 1A or 1B substances. According to Section 10 (5) GefStoffV, an action plan must be implemented immediately if, despite all technical protective measures, the occupational limit value is no longer complied with or the activities are at medium risk. The aim is to comply with the occupational limit value or to move into the lower risk range. The action plan specifies which project is to be used to reduce exposure and over what period of time.
GSA measuring devices SG10-2 – Measuring exposure to chromium(VI)
The SG10-2 GSA measuring device is suitable for detecting possible exposure to chromium(VI) compounds in areas with a risk of exposure. The Deutsche Gesetzliche Unfallversicherung (DGUV) recommends the use of this measuring device. The SG10-2 was specially developed for hazardous substance measurement of inhalable E-dust and respirable A-dust and achieves a volume flow of 1-12 l/min.
Sampling of chromium(VI) with the SG10-2 according to IFA 6665
Before measuring with the SG10-2, the filter holders with the appropriate quartz fiber filter must be inserted into the GSP sampling system GSP 10. A volume flow of 10 l/min is then set on the measuring device.
During chromium(VI) sampling, the pump of the SG10-2 draws in the contaminated air. The dust particles are deposited on the quartz fiber filter. A measurement period of four hours is recommended for the entire sampling. This achieves a volume of 2.4 m³, which is suitable for detecting one tenth of the assessment standard (1 µg/m³). After the measurement, the filters are removed, sealed and prepared for further analysis. This sample volume meets the requirements of IFA measuring method 6665 and enables sufficient detection sensitivity for the assessment of chromium(VI) contamination in accordance with TRGS 910.
Analysis of the sampled chromium(VI) concentrations
For the analysis of the sampled concentrations, we recommend our partner company, GSA Gesellschaft für Schadstoffanalytik mbH, which specializes in the analysis and evaluation of pollutants such as chromium(VI). The chromate concentration is analyzed by photometric determination of the chromium(VI) content according to IFA measuring method no. 6665 in conjunction with EN ISO 18412:2006. This method enables the quantitative recording and evaluation of chromium(VI) exposure at the workplace.
Sources:
Image source: 123rf.com © mikkiorso, image no. 244157393
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