Health Damage from Exposure to Chromium and Its Compounds

Detailed article on the health risks associated with occupational exposure to chromium and its compounds. Learn how to identify, prevent and protect yourself, with a focus on Portuguese legislation.

2026-07-17 · 5 min · Segurança no Trabalho

Occupational exposure to chromium and its compounds, whether in the form of dusts, fumes or mists, via inhalation, ingestion or dermal contact, represents a significant health risk. For this reason, in addition to the correct identification, assessment, prevention and protection of the risk, specific health surveillance of exposed workers is essential.

General Characteristics of Chromium

Chromium is a greyish-white metal, highly resistant to wear. It has three valence states: 2+, 3+ and 6+. Bivalent derivatives are highly unstable, oxidising easily into trivalent derivatives. However, hexavalent bonds are considered the most dangerous.

Chromium VI (Hexavalent) – Compounds

This is the most toxic.

• Soluble compounds: Ammonium, potassium and sodium chromate; potassium and sodium dichromate; chromium trioxide (chromic anhydride or chromic acid).
• Insoluble/low-solubility compounds: Barium, lead, calcium, strontium and zinc chromate; mixed zinc chromate and potassium chromate, among others.

Chromium III – Compounds

• Chromium acetate, chromium oxide, chromium orthophosphate, chromium pyrophosphate, chromium sulphate, chromium sulphide, among others.

Main Activities with Risk of Exposure

In accordance with the framework of occupational diseases, Portuguese legislation, namely the Lista de Doenças Profissionais (approved by Portaria n.º 23/2024, of 16 January), identifies various activities with a risk of exposure to chromium, both trivalent and hexavalent, and its compounds. Prevention must be a priority in these contexts.

Some of the high-risk activities include:

• Preparation, use and handling of chromium compounds, especially chromates, alkaline dichromates and chromic acid.
• Manufacture of catalysts, chemicals for tanneries and wood treatment products containing chromium compounds.
• Manufacture and use of pigments, dyes and paints based on chromium compounds.
• Sawing and machining of wood treated with chromium compounds.
• Spray application of paints and varnishes containing chromium.
• Chrome tanning of hides.
• Preparation of photogravure plates using bichromated colloids.
• Manufacture of matches.
• Electroplating and surface treatment of metals with chromium.
• Pickling and cleaning of metals and glass (sulphochromic acid or chromic acid).
• Manufacture of alkaline chromates.
• Lithography.
• Manufacture of stainless steels.
• Work involving welding and flame cutting of stainless steels.
• Manufacture of cement and its derivatives.
• Processing of waste containing chromium.

Health Effects

Occupational exposure to chromium and its derivatives has been associated with health effects of varying severity. It is crucial to adopt robust safety measures in workplaces to minimise exposure and, consequently, reduce the number of associated diseases.

Adverse effects during occupational exposure are mainly caused by hexavalent (VI) compounds. This is due to the greater ease of absorption of water-soluble hexavalent chromium compounds through the pulmonary route and their oxidising action on the respiratory tract. In these cases, chronic bronchitis, asthma, mucosal hypertrophy and, eventually, cancer may occur. In exposed workers, an accumulation of chromium is observed in the lungs, liver and kidneys. Hexavalent compounds are those that present the highest toxicity.

Chromium is irritating and corrosive to the skin and mucous membranes, increases the incidence of lung and paranasal sinus cancer, and is a major respiratory and skin sensitiser.

Zinc, calcium, strontium and potassium chromates are classified as Group I carcinogenic substances by the IARC (International Agency for Research on Cancer), which means they are proven to be carcinogenic to humans. Other chromium compounds are classified in Group 2, as potentially carcinogenic to humans.

Acute Toxicity

Ingestion of hexavalent chromium compounds, usually accidental, causes gastrointestinal symptoms with vomiting, abdominal pain, diarrhoea and intestinal bleeding.

In some cases, it can lead to death from cardiocirculatory shock. If the patient survives, they may develop renal failure due to acute tubular necrosis. It can also cause liver failure, coagulation disorders or intravascular haemolysis.

Chronic Toxicity

Exposure to hexavalent compounds can cause:

• Dermal changes: Allergic contact dermatitis with erythematous or vesicopapular lesions (eczema), highly pruritic, predominantly on the hands and forearms.
• Irritant contact dermatitis: Painless and sometimes pruritic ulcers of 5 to 10 mm on the back of the hands and fingers, known as "chrome holes".
• Irritative changes and atrophy of the nasal mucosa: In the area of the nasal septum, known as "Hajek's ulcer", which can lead to septal perforation.
• Bronchopulmonary changes: Asthma and chronic bronchitis, with pharyngeal irritation, cough, retrosternal pain and bronchospasm due to an irritant and/or sensitising (allergic) effect.
• Chromium VI is a pulmonary and paranasal sinus carcinogen (certain pigments with very low solubility, such as calcium, strontium and zinc chromates).
• Hepatotoxicity: Jaundice, choluria, hypocholia or acholia, hepatomegaly.
• Renal failure.

Especially Sensitive Workers

The assessment must be individualised, considering a history of anaemia, mild renal failure, chronic respiratory disorders and skin diseases. In clinical situations where there may be difficulty in the differential diagnosis between the underlying disease and the potential effects of exposure to these substances, exposure should be temporarily avoided.

The Importance of Mandatory Vocational Training

The Portuguese Labour Code, in its Article 131 of the Portuguese Labour Code, establishes the obligation of continuous vocational training for workers, for a minimum of 40 hours annually. This training is crucial for the prevention of occupational risks, including exposure to hazardous substances such as chromium. Through appropriate training, workers can acquire the knowledge and skills necessary to identify risks, correctly use collective and personal protective equipment (EPI), and follow safety protocols, thereby ensuring a safer working environment and minimising health damage.