N-nitrosamines are typically not intentionally produced but usually formed from secondary amines and nitrosating agents under certain reaction conditions. Typical workplaces where N-nitrosamines can occur are in the rubber, leather, metalworking and chemical industry. More than 350,000 workers are employed in the EU alone in the rubber industry; additionally about 260,000 workers are estimated to be exposed to metal-working fluids. Many N-nitrosamines are classified according to CLP as Carcinogenic Category 1A, 1B or 2. They are suspected of being carcinogenic in humans by damaging genetic material and causing stomach cancer. Dermal skin contact can lead to allergic contact dermatitis.

Where risks occur

Exposure to N-nitrosamines may occur in the rubber industry while tasks such as weighing, mixing, semi-finished product processing, vulcanization and post-treatment are performed. The respective products are potential sources of exposure to N-nitrosamines as well. Exposure occurs also in the metalworking industry during maintaining and servicing machines, manual handling of machine tools with the close presence of an operator and the likelihood of spraying, splashing or evaporation of the substances and mixtures during operation. Production and use of amines in the chemical industry, as well as decanting and filling operations of amines and their use in further chemical processes e.g. coatings by the coagulation process and production of polyacrylonitrile fibres, are workplaces where N-nitrosamines can occur. Further workplaces where exposure may occur can be found in the leather industry, in electronic industry and in foundries.

More about the substance

N-nitrosamines are neither intentionally produced, nor typically used. N-nitrosamines are usually formed from secondary amines in contact with other nitrogenous compounds and nitrosating agents. Nitrosating agents are nitrous acid and its salts, the nitrites, nitrogen oxides from engine exhaust or organic nitro and nitroso compounds.

Secondary amines can be present in chemical additives or as ingredients from ready-to-use products. Well-known secondary amines with the potential to generate N-nitrosamines include diethylamine, diethanolamine, diethylpropylamine, morpholine or pyrrolidine.
Secondary amines can also be formed from other nitrogen-containing compounds in relevant amounts e.g. by hydrolysis, thermic or biogenic decomposition. Typical secondary amines can also be found among corrosion inhibitors, vulcanisation accelerators, plant protection agents, specific cleaning agents, solvents and water-miscible or water-mixed cooling lubricants such as metalworking fluids.

How symptoms can affect you

Some nitrosamimes have irritating properties. Respiratory diseases and contact dermatitis have been reported in the context of nitrosamine exposure at the workplace, e.g. in rubber industry.

Exposure to N-nitrosamines has been linked to a wide variety of cancer types, e.g. development of cancer in the bladder, stomach, esophagus, prostate, pancreas and liver leukemia and multiple myeloma.

The latency period between exposure and cancer development has been estimated to be 15 years.

What you can do

The first measures should be risk elimination and prevention. Replace secondary amines with suitable substitutes, if applicable, or reduce the concentration of secondary amines as much as possible. To reduce the risk of N-nitrosamine formation, keep nitrosating agents or precursors such as nitrit away and keep the concentration of secondary amines low. Check or monitor the maximum concentration of secondary amines, nitrosating agents or the pH-value in products. Comply with national use restrictions, if present. If substitution is not possible, implement regular exposure measurements to check if your protection measures in place are effective or whether further actions need to be taken. Workers need to be aware of the effects of exposure and should be encouraged to report symptoms of skin sensitisation. Technical solutions like closed systems or exhaust of process-related N-nitrosamines are alternatives if substitution is not possible. Make workers continuously aware of the effects of exposure. Additionally, train workers on hazards, safe work practices and on effective hygiene measures. Ensure that workers have adequate personal protective equipment, such as protective clothing. Since nitrosamines easily penetrate common glove materials, skin contact cannot be ruled out even when gloves are worn. Make sure to choose gloves made from adequate material e.g., nitrile rubber. Protection also depends on the extent to which the material is also suitable for the accompanying hazardous substances. Change contaminated gloves immediately. Personal protective equipment should only be used as a last resort, after the possible technical solutions have been introduced.

References: AGS, FIOH, DGUV, HSE, BAuA, Statista