25. Industrially manufactured or formed in situ: unequal control

In regulations and in public perception, chromium(VI) compounds are considered almost exclusively in their industrially manufactured form, as the Udy patent describes it as the product of a targeted process. Strict requirements apply to this form: in the EU, manufacture and use are subject to authorisation and, in future, to a restriction, workplaces are monitored, emissions are limited, and mixtures such as chromate-containing paints and primers carry hazard labelling with a pictogram and the hazard statement H350. [1, 3, 59]

In-situ formation, by contrast, remains largely disregarded or is pushed aside. Calcium and sodium chromate form during intended operation on hot components, in insulation materials and in combustion residues, without a manufacturer placing them on the market, without labelling and usually without a safety data sheet describing the condition after use. Those exposed are fitters, service technicians, insulators, motor mechanics, overhaul personnel and waste disposal workers, often without knowing it. The health consequences are the same as with the industrially manufactured form: lung cancer, cancer of the nose and paranasal sinuses, skin ulcers and allergic contact dermatitis. In addition, there is contamination of soil and water via dusts, ashes and waste. [53, 56]

Regulatory developments

Australia is already taking the step towards minimisation: from 1 December 2026, the Australian authority Safe Work Australia will no longer set workplace exposure limits for non-threshold genotoxic carcinogens; chromium(VI) compounds are expressly included. The exposure limit is replaced by the obligation to eliminate exposure or to minimise it so far as is reasonably practicable (SFAIRP, comparable to the ALARP principle). [58]

In the EU, the European Chemicals Agency ECHA proposed a restriction on chromium(VI) substances in April 2025, intended to replace the existing authorisation procedure. Under this proposal, only certain uses would remain permitted under strict conditions, with workplace exposure limits of between 0.1 and 5 µg Cr(VI)/m³ depending on the use, as well as emission limits for air and water; all other uses would be prohibited. [59]

The broad concept of use in the European REACH Regulation is decisive here. Under Article 3 point 24, “use” means any “processing, formulation, consumption, storage, keeping, treatment, filling into containers, transfer from one container to another, mixing, production of an article or any other utilisation”. Accordingly, even the storage of removed thermal insulation contaminated with chromate dusts can constitute a use; the reuse of such insulation is all the more a use. If it does not fall under the uses permitted in future, it is prohibited. [60]

Unequal control in practice: the comparison with asbestos

The unequal treatment does not end with the rules; it continues in practice. Industrially manufactured chromium(VI) is used in closed systems, is subject to authorisation, is labelled, is supplied with a safety data sheet and is handled by instructed personnel. Chromium(VI) formed in situ, by contrast, is met as a deposit on a surface. It has no manufacturer, no supplier, no labelling and no safety data sheet. It therefore falls out of the category of hazardous substance and into the category of dirt. It is treated accordingly, with rags, brushes, vacuum cleaners, compressed air and spray products, by the maintenance and cleaning staff already on site. The widespread term “neutralisation” comes from that same world of language and not from chemicals law.

The comparison with asbestos shows the gap. Both substances are classified as carcinogenic to humans, and with both the danger arises not in the installed condition but when dust is released during maintenance, removal or cleaning. For asbestos this has produced a closed procedural regime. The German TRGS 519 in the version of 28 February 2025 requires under number 3.2 that demolition, remediation and maintenance work be notified to the competent authority “at the latest 7 days before the work begins”. Number 2.7 governs the required expertise and its proof, and numbers 5.1 to 5.3 the responsible person, the supervisor and the skilled personnel. For weakly bound asbestos products, numbers 14.1 to 14.3 require containment and air handling measures as well as personnel and material locks [97].

For the chromates formed in situ none of this exists. There is no duty to notify before work begins, no dedicated proof of expertise, no prescribed supervisor, no clean and dirty zone system and no approved specialist contractors. The German TRGS 561 requires personal protective equipment, low dust working and the substitution check (section 6), but it does not set up a procedural regime with notification, proof of expertise and containment. Nobody would think of treating an asbestos-containing board with a spray by hand and then wiping it down. With a chromate-loaded hot component this is exactly the usual practice.

On two points the classification even argues against this unequal treatment. Sodium chromate carries three skin-related hazard statements, harmful in contact with skin (H312), corrosive (H314) and skin sensitising (H317) [65]; asbestos carries none in its harmonised classification. Calcium and sodium chromate are also classified as very toxic to aquatic life with long lasting effects (H400, H410) [64, 65], while the harmonised classification of asbestos, Carc. 1A (H350) and STOT RE 1 (H372), states no environmental hazard [98]. In the dermal and in the environmental dimension the chromates are therefore classified more strictly than the substance for which the closed procedural regime applies.

The assessment of skin contact leads straight to the highest rank. The German TRGS 401 in the version of October 2022, last amended on 19 September 2024, grades the hazard by type of contact in table 2 of section 4.2. For the row “Absorbed through the skin and at the same time having the hazardous properties listed alongside”, carcinogens of category 1A or 1B (H350) are graded “h”, that is, high hazard, for every type of contact, with no threshold for duration or area. Skin sensitising properties alone (H317) lead to that grade only for contact of more than 15 minutes per working day over a large area, and under paragraph 4 also where practical experience shows sensitisation in a considerable number of employees [99].

Chromium(VI) compounds meet both criteria, and the marking is officially assigned. Under section 3.2.3 paragraph 2, the German TRGS 401 takes the marking “H” for substances absorbed through the skin from the German TRGS 900, 905 and 910; where a substance is not listed there, the MAK and BAT value list of the German Research Foundation may be used as a further source of information [99]. In annex 1 of the German TRGS 910, chromium(VI) compounds are listed at 1 µg/m³ of the inhalable fraction with an excursion factor of 8 and the note “see TRGS 561”, but without a skin marking [101]. The MAK and BAT value list 2026, communication 62, by contrast carries both markings under “Chromium(VI) compounds (inhalable fraction)”: skin absorption “H” and sensitisation “Sh”, together with carcinogenicity category 1 and germ cell mutagenicity category 2. Expressly excluded from the H marking are only barium, lead, strontium and zinc chromate, and from the Sh marking only barium and lead chromate. Calcium and sodium chromate, the compounds treated here, fall under none of these exceptions [102].

The grading of skin contact is therefore unambiguous. A substance that is absorbed through the skin according to the MAK and BAT value list and at the same time belongs to carcinogenicity category 1 falls into the row “Absorbed through the skin and at the same time having the hazardous properties listed alongside” in table 2 of the German TRGS 401 and is graded there as a high hazard for every type of contact, irrespective of duration and area [99]. The additional Sh marking and the harmonised classification skin sensitisation 1, H317, come on top of that; the Institute for Occupational Safety and Health of the German Social Accident Insurance names the routes of uptake for chromium(VI) compounds as “inhalation, skin absorption” [100]. For asbestos no comparable skin assessment exists, because its harmonised classification contains no skin-related hazard statement.

This raises the question of what justifies the difference in handling. Both groups of substances are classified as carcinogenic, the release mechanism via dust during maintenance and removal is the same, and for calcium chromate the potency is documented in animal studies (section 24). The difference lies not in the substance, but in the fact that the one was supplied as a product and the other arose in operation.

Duties before work begins: investigation, assessment and the ban on starting

In the legal systems considered here, the duties before work begins are for the most part framed without naming a specific substance. The German Hazardous Substances Ordinance requires the employer, in section 6 paragraph 2a, to examine the information provided to him under section 5a paragraph 1 as to whether hazardous substances are released from the structural or technical installation during the activities and can endanger the health of the employees. Where the information from the party commissioning the work is not sufficient, he has to carry out this examination himself under paragraph 2b and to make use of external expertise where he lacks the necessary knowledge, in particular where a technical investigation becomes necessary. If a technical investigation is necessary in order to carry out the risk assessment and to determine the protective measures, it is, under paragraph 2c, a precondition for carrying out the activities. Section 7 paragraph 1 prohibits taking up the activity before the risk assessment has been carried out and the necessary protective measures have been taken, and section 6 paragraph 8 sentence 1 requires the documentation for the first time before the activity is taken up, irrespective of the number of employees. The term used in these paragraphs is hazardous substances; asbestos is not named there. [120]

The year of construction entry appears elsewhere. Section 5a paragraph 2 of the German Hazardous Substances Ordinance requires the party commissioning the work, for the purpose of establishing whether asbestos is present, to state the date on which construction began where the year of construction lies between 1993 and 1996, and otherwise the year of construction. For chromates formed in situ this entry has no significance, because the compound is not introduced during construction but arises in operation. An installation erected in 2024 with chromium-alloyed hot components and calcium-bearing insulation falls under the same wording as existing older stock. [120]

The Dutch Arbeidsomstandighedenbesluit requires, in Article 4.2 paragraph 1, the assessment of the nature, degree and duration of the exposure within the Risico-Inventarisatie en -Evaluatie, even where such activities are not currently carried out. Paragraph 3 requires the determination of the exposure level, paragraph 7 the comparison with the limit value laid down for the substance and paragraph 8 the review as soon as new activities involving hazardous substances are begun. Article 4.1b paragraph 2 lists this assessment as one of the conditions under which the general duty of protection is regarded as fulfilled. Article 4.2 contains no express ban on starting before the assessment. It appears, asbestos-related, in Article 4.54a paragraph 1, under which the presence of asbestos is to be fully inventoried before demolition or dismantling, removal or clearing up after an incident is begun, carried out by a company certified for asbestos inventory work. [121]

In the United Kingdom the ban stands, without naming a specific substance, in Regulation 6(1) of the Control of Substances Hazardous to Health Regulations 2002: “An employer shall not carry out work which is liable to expose any employees to any substance hazardous to health”, as long as there is no “suitable and sufficient assessment of the risk created by that work” and the steps following from it have not been implemented. Regulation 6(2) lists what the assessment has to take into account, including the information from the supplier together with the safety data sheet, the level, type and duration of the exposure, and activities such as maintenance that can lead to high exposure. Asbestos-related, Regulation 5 of the Control of Asbestos Regulations 2012 is added, under which an employer may not carry out demolition, maintenance or other work which exposes or is liable to expose employees to asbestos unless he has either carried out a “suitable and sufficient assessment” of the presence, type and condition of the asbestos or, in case of doubt, assumes its presence and applies the Regulations. [122, 123]

In the United States, 29 CFR 1926.1126(d)(1) obliges every employer whose workplace or work operation falls under the standard to determine the eight hour shift average values for each employee exposed to chromium(VI). Under (d)(2) this is done by means of an initial measurement with a sufficient number of personal air samples for each shift, job classification and work area, and under (d)(3) by means of a combination of monitoring data, historical data or objective data. Under (d)(2)(vi), additional measurements have to be carried out where the process, raw materials, equipment, personnel, work practices or protective measures change in such a way that new or additional exposures can arise. The chromium(VI) standard contains no ban on starting of the kind found in German section 7 paragraph 1 or British Regulation 6(1). The structural counterpart is found in the asbestos standard: 29 CFR 1926.1101(k)(2)(i) obliges the owners of buildings and installations to determine the presence, location and quantity of asbestos-containing material and material presumed to contain asbestos, and the definition in (b) presumes an asbestos content for thermal system insulation and for applied surfacing materials in buildings with a year of construction no later than 1980, as long as this presumption has not been rebutted under (k)(5). The initial exposure assessment under (f)(2)(i) has to be carried out by a competent person immediately before or at the start of the work. [124, 125]

For the application case treated here, the German TRGS 561 ties the protective regime, in section 5.9.3 paragraph 5, to activities on industrial components “on which chromium(VI) contamination is present or in respect of which it cannot be ruled out”. The duty therefore arises before the finding. The absence of a measurement does not establish an exclusion, and the investigation is the route by which an exclusion could be demonstrated at all. [19]

As an assessment: two of the four legal systems contain the ban on starting before the assessment in a form that does not name a specific substance, Germany through section 7 paragraph 1 of the Hazardous Substances Ordinance and the United Kingdom through Regulation 6(1) COSHH. In the Netherlands and the United States the prior duty lies in the general hazardous substances rule as a duty of assessment and determination, while the ban brought forward in time and the presumption rule stand in the asbestos regime. The unequal treatment described in the previous subsection is therefore also reflected in the structure of the rules, as a difference in procedural depth and not as a difference in principle.