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Measuring workplace and environmental limit values for chromium trioxide in compliance with the law

With the use of the authorisation for chromium trioxide (chromium(VI) oxide), industrial companies are obliged to comply with and measure required workplace and environmental values. What does this mean in real terms for companies affected by this and how can they meet the high demands placed on them?

The European Chemicals Regulation on the Registration, Evaluation, Authorisation and Restriction of Chemicals, known as REACH for short, back in 2012, placed chromium trioxide (chromium(VI) oxide) on the list of substances of very high concern (SVHC). This is because chromium trioxide has been classified as both carcinogenic and mutagenic.

From then on, companies that wanted to continue using chromium trioxide had to prove the safe handling and the necessity for using this substance in an application for authorisation. ECHA (European Chemicals Agency) had taken over the review of the applications and developed recommendations for authorisation periods and conditions for the applicants.

On 22 December 2020, the European Commission officially approved the authorisation request for the continued use of chromium trioxide until 21 September 2024. At the same time, the users concerned were requested to notify ECHA of their continued use of chromium trioxide by 22 March 2021.

With the authorisation, operators are obliged to comply with and measure the required workplace and environmental limit values, i.e., air and wastewater measurements. All measurement results must be reported to ECHA by 18 December 2021, and annually thereafter.

These are the authorisation conditions for the use of chromium trioxide in detail:

  • Companies concerned must regularly monitor the Cr(VI) exposure of their employees and the environment.
  • Authorised and representative measurements must be carried out to validate the exposure scenarios.
  • There is a requirement to minimise the exposure of workers and the environment. This is checked by the responsible authority.
  • The measurement results must be submitted to ECHA and made available to the national authority in charge if required.
  • Measurements include both sampling of employees and/or the environment and analysis of samples to quantify Cr(VI) exposure in the context of work processes.
  • First measurements of workplace exposure must be carried out within six months after issuance of the authorisation of 18 June 2021.
  • The submission of the measurement results to ECHA must have taken place within one year of the authorisation decision being issued (18 December 2021).
  • The measurements must be repeated annually.

Measurement strategy for workplace measurements of chromium(VI)

Workplace exposure measurements can be carried out as person-related (person-carried, mobile on employees) or workplace/area-related (stationary) measurements. A person-related measurement depicts the individual employee exposure in a more reliable way and should preferably be used. Workplace air monitoring is part of an exposure measurement procedure established for workplaces with possible exposure to chromium trioxide from released dusts or aerosols.

An important part of the measurement planning are the requirements of the process characteristics of the measurement procedure, such as LOD (Limit of Detection), LOQ (Limit of Quantification) and the limit value to be complied with. Based on these parameters, the optimal measuring equipment is selected, and the measuring duration is determined. This is the only way to ensure a reliable and representative Cr(VI) quantification at the workplace.

The measurement of air in the workplace must be repeated regularly and annually, until the results prove with certainty that the exposure hazard has been minimised in the long term. Only then can the frequency of testing be reduced. In principle, however, new exposure measurements must be carried out if changes are made to the production process.

Expertise in chromium trioxide emission measurements and workplace measurements

The requirements for chromium trioxide emission measurements are very strictly regulated by legal requirements of the Federal Immission Control Act (BImSchG), the Technical Instructions on Air Quality Control (TA-Luft), and the relevant DIN EN and VDI standards. The measurements may only be carried out by notified and accredited* measuring bodies according to §29b BImSchG. WESSLING operates an approved measuring station at several locations nationwide and has many years of experience in the measurement of chromium trioxide at all chromium(VI) processed industrial plants.

In addition, the WESSLING measuring station is accredited in accordance with Section 7 Para. 10 of the Hazardous Substances Ordinance (GefahrStoffV)* and thus fulfils the highest legal requirements and conditions in accordance with DIN EN ISO/IEC 17025. Our measuring laboratory has many years of experience in determining and assessing hazardous substances such as chromium(VI) and other environmental influences in the air of workplaces that are hazardous to health.

We conduct both work area analyses, exposure measurements and control measurements in accordance with the Technical Rules for Hazardous Substances (TRGS) 402. With our professional expertise and state-of-the-art technical equipment, we are happy to be of service to you.


*Testing laboratory accredited by DAkkS according to DIN EN ISO/IEC 17025:2005. The accreditation is only valid for the scope of accreditation listed in the annex to the certificate [D-PL-14162-01-00].

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