In brief
Nickel plating of metals is in the very hazardous class in the 2025 list. The main risks on plating lines are splashes from acid and alkaline baths, metal and acid mists rising from the bath surface during electrolysis, mixing of incompatible chemicals, rectifier electricity in a wet environment and, in hot-dip galvanising, molten zinc. Chromium and nickel compounds are on the list of occupational diseases; health surveillance focuses on the skin, nose and respiratory system.
Plating plant safety: class and basic obligations
Plating is the coating of the surface of a metal part with another metal to give it corrosion resistance or appearance. In electroplating, the part is immersed in a bath in which metal salts are dissolved, and metal is deposited on the surface by direct current; in hot-dip galvanising, the part is dipped into molten zinc. In Bursa’s automotive and metal industry, plating is an intermediate process in the supply chain of many parts.
In the Workplace Hazard Classes List renewed in 2025, 25.51.01 Nickel plating of metals is in the very hazardous class. Other types of plating, such as zinc, chrome or hot-dip galvanising, may have a different code; check your own code from your SGK (Social Security Institution) registration. Let us show the basic obligations in a very hazardous plating plant with an example of 35 employees:
| Obligation | Rule in the very hazardous class | For 35 employees |
|---|---|---|
| OHS specialist | 40 min per employee per month, class A certificate | 1,400 min per month (about 23.3 hours) |
| Workplace physician | 15 min per employee per month | 525 min per month (about 8.75 hours) |
| Other health personnel (DSP) | 10 min per employee per month for 10–49 employees | 350 min per month |
| Periodic examination | Every year | Every employee once a year |
| Basic training | At least 16 lesson hours; job-specific risks at least 4 hours and face to face; at least 8 hours of refresher training every year | Annual plan for 35 people |
| Risk assessment | At least every 2 years and whenever there are changes | Immediately on a bath or process change |
| Firefighting, rescue and protection teams | At least one support staff member each for every 30 employees | At least 2 people in each team |
| First aider | 1 for every 10 employees | At least 4 people |
For details of the obligations, see our article on obligations of very hazardous workplaces, and for your own hours calculation, the OHS obligation calculator tool.
Hazards along the line
An electroplating line usually consists of degreasing, rinsing, acid activation or pickling, the plating bath, rinsing again and drying. Each stage has a different hazard:
| Stage | Chemical or energy | Main risk |
|---|---|---|
| Degreasing | Hot alkaline solutions | Skin and eye burns, hot vapour |
| Pickling and activation | Hydrochloric or sulphuric acid | Splashes, acid vapour, hydrogen formation |
| Nickel and chrome baths | Metal salts, chromic acid | Metal and acid mists, skin sensitisation |
| Cyanide baths (some zinc, copper, silver processes) | Cyanide salts | Release of toxic gas on contact with acid |
| Rectifiers and busbars | Low voltage, high current | Heating, arcing, leakage in a wet environment |
| Racking and handling | Cranes, racking bars, heavy baskets | Crushing, falling loads, manual handling |
Acid baths and chemical splashes
The acid bath is the most frequent source of chemical burns on a plating line. The measures are addressed in this order:
- Correct preparation. When diluting, acid is added to water slowly while stirring; the reverse causes violent heating and splashing. Bath top-ups are done by people who know the job, following written instructions.
- Controlled transfer. Chemicals are not poured into the bath from drums by hand; a suitable pump or pouring device is used.
- Separating incompatible chemicals. Cyanide baths and salts are physically separated from acid baths and acid stores; drip trays and wastewater lines are also arranged so that they do not mix. Oxidisers such as hypochlorite are not kept in the same place as acids either. Sections 7 and 10 of the safety data sheet show which substances are incompatible with what; for how to read it, see our article on the safety data sheet.
- PPE. Face shield and goggles, chemical-resistant gloves, apron and boots. The glove material is chosen according to the chemical used; see choosing work gloves.
- Emergency equipment. Having an eyewash and emergency shower close to the bath area and easy to reach, and running and testing them regularly, ensures the first minutes are not lost in a splash.
For what to do in spills and leaks, see our article on chemical spill response.
Metal mists, vapours and ventilation
During electrolysis, gas bubbles forming at the electrodes burst at the bath surface and carry the solution into the air as fine droplets. In chrome plating, this mist contains hexavalent chromium; nickel baths carry nickel salts. Acid vapour rises from pickling baths, and hydrogen forms in some baths.
The basic measures:
- Local exhaust at the edge of the bath. The mist is extracted at source, just above the bath surface; a general extractor fan in the ceiling does not capture the mist passing through the employee’s breathing zone.
- Covering baths. Lids and surface covers when not in use, and enclosed compartments on automatic lines.
- Ventilation against hydrogen. Areas below the ceiling and enclosed sections where hydrogen may accumulate are ventilated, and ignition sources are controlled in these areas.
- Environmental measurement. Chromium, nickel and acid vapour measurements are planned with authorised laboratories and the results are incorporated into the risk assessment. For situations requiring measurement, see our article on workplaces where environmental measurements are mandatory.
Rectifiers, busbars and the wet environment
The rectifiers that supply plating baths deliver very high current at low voltage. Although low voltage seems to reduce the risk of electric shock, busbars and rack connections heat up, arcs can form at loose contacts and the mains side of the rectifier is at full voltage. Wet floors and cables and junction boxes damaged by acid vapour increase the risk of leakage. The internal electrical installation and earthing are inspected once a year by competent persons; when maintenance is carried out on rectifiers and bath equipment, the power is isolated and locked out. For rules on switchboards, see our article on electrical panel safety, and for energy isolation, our article on lockout and tagout.
Additional risks in hot-dip galvanising
Unlike electroplating lines, galvanising safety also involves the risk of molten metal. The zinc kettle operates at several hundred degrees, and moisture on a part entering the kettle or liquid trapped in a closed cavity can vaporise instantly and make the molten zinc splash. That is why parts are dried before dipping, the vent holes of closed sections and pipes are checked, and heat-resistant protective clothing and face shields are used around the kettle. Fumes rising from the flux and the kettle surface are removed by local exhaust. Since parts are dipped with an overhead crane, checks on hangers, slings and the crane are also part of daily work; see overhead crane safety. For the heat stress that comes with long periods at the kettle, water, breaks and rotation are planned.
Health surveillance for chrome plating and nickel
The list of occupational diseases explicitly mentions plating work:
- Chromium and its compounds (A-5): “Galvanotechnics (electrolytic chrome plating)” is among the work with a disease hazard. Symptoms listed include dermatitis, “bird’s eye” ulcers on the skin, ulceration and perforation of the nasal septum, upper respiratory tract irritation and bronchial carcinoma.
- Nickel and its compounds (A-9): “Electrogalvanisation (nickel plating)” is on the list; chronic effects include skin diseases such as itching, redness, eczema and skin ulcers.
- Cyanides and cyanogen compounds (A-3): The use of cyanogen compounds in the galvanisation of metals such as gold, silver, nickel, cadmium and copper is listed among work with a disease hazard.
In health surveillance for chrome plating, the workplace physician therefore focuses particularly on skin examination of the hands and forearms, examination of the inside of the nose and the respiratory system. The legislation has no fixed frequency for tests; the physician decides according to exposure. Where necessary, biological monitoring methods such as lung function testing and metal levels in urine can be used. We explained how lung function test results are monitored in our article on the lung function test. Whether an employee who develops nickel sensitivity can continue working with the same exposure is decided by the workplace physician.
For risk assessment and measurement planning in plating plants, see our risk assessment service, and for monitoring chromium and nickel exposure, our health surveillance service. Sector-specific notes are on our metal and machinery and automotive supplier industry pages; preparation for OEM audits is in our article on the supplier OHS audit.
Frequently Asked Questions
Which hazard class is nickel plating in?
In terms of hazard class, nickel plating is in the top group: in the 2025 Workplace Hazard Classes List, 25.51.01 Nickel plating of metals is in the very hazardous class. Since other types of plating may have a different code, check your own activity code.
Is general ventilation enough on a plating line?
Usually not. Metal and acid mists form at the bath surface; that is why local exhaust at the edge of the bath and covering baths not in use are the basic measures. Adequacy is verified by environmental measurement.
Why is a cyanide bath kept separate from acid?
Cyanide salts can release toxic gas on contact with acid. That is why cyanide baths, their stores, drip trays and waste lines are physically separated from acids.
Which examinations are carried out for plating workers?
In the very hazardous class, the periodic examination is carried out every year. The workplace physician focuses on examining the skin, nose and respiratory system, and decides according to exposure whether tests such as lung function testing and biological monitoring are needed.
A risk assessment that identifies and scores hazards on site, links each measure to an owner and a date, and has a clear renewal schedule.
Bursa SİSTEMER OSGB Technical Team — written from the field experience of our OHS specialists and workplace physicians. Legal information is valid as of the publication/update date; contact us for an assessment specific to your business.