In brief
Four risks coexist in dyeing and finishing departments: corrosive and sensitising chemicals, hot water and steam, dyeing vessels operating under pressure, and permanently wet floors. The vessels of dyeing machines undergo periodic inspection at least once a year under Annex III; chemicals require weighing, dissolving and transfer rules based on the safety data sheet. Textile bleaching and dyeing (13.30.01) is in the hazardous class in the 2025 list.
Why is dyehouse safety treated separately?
In a textile business, the risks of the spinning and weaving departments are mainly from machinery, noise and dust. In finishing and dyeing, the picture changes: caustic and peroxide are used in pre-treatment (desizing, scouring, bleaching), dyestuffs and auxiliary chemicals in dyeing, and finishing chemicals in final treatments; all of this goes hand in hand with hot water, steam and pressure. Dyehouse safety therefore requires managing chemical, thermal and mechanical risks at the same time.
In the hazard class list renewed in 2025, textile bleaching and dyeing (NACE 13.30.01) is in the hazardous class; it was very hazardous in the 2012 list. The lower class does not mean the risks have decreased: the same chemicals and the same vessels are still on site. In Bursa, dyehouses operate in TOSAB, the Bursa Textile Dyehouses Specialised OIZ in Badırga, Nilüfer, and in other industrial zones. For the risks of weaving departments, see our article on OHS in weaving businesses.
Textile finishing chemicals: hazards and measures
Most chemicals used in a dyehouse are well-known substances on their own; the hazard arises from their use in large quantities, at high temperature and close to one another. The Regulation on Health and Safety Measures for Work with Chemical Substances requires the employer to identify hazardous chemicals and assess the risks on the basis of safety data sheets (SDS).
| Substance group | Typical hazard | Control measure |
|---|---|---|
| Caustic soda (NaOH) | Severe burns to skin and eyes; heat is released when dissolved in water | Closed transfer or dosing pump; face shield, chemical-resistant gloves and apron; when dissolving, caustic is added to water |
| Hydrogen peroxide | Oxidiser; fire risk on contact with organic matter; skin and eye irritation | Separate and cool storage; for spills, a suitable absorbent instead of sawdust or rags |
| Sodium hydrosulphite | Can self-heat with moisture; releases toxic gas on contact with acid | Dry storage with the lid closed; shelving separate from acids |
| Sodium hypochlorite | Releases chlorine gas when mixed with acid | Not kept in the same tray or line as acids; separate labelled line |
| Acetic and formic acid | Corrosive; vapour irritates the respiratory tract | Local ventilation; storage suitable for the acid class |
| Powdered dyestuffs | Inhalation of dust; the SDS of many reactive dyes carries a respiratory sensitisation warning | Local exhaust during weighing and dissolving; liquid or granular form where possible; suitable respiratory protection |
The riskiest point of the dyehouse is often the weighing and dissolving section, also known as the colour kitchen. Here powdered dyes are opened, weighed and dissolved in hot water. The order of priority for this section is: local exhaust, an enclosed weighing arrangement, drip trays against spills, and PPE only when these are not enough. Once sensitisation has developed, even very low exposure can cause complaints; that is why respiratory complaints among weighing staff should be reported to the workplace physician.
To read SDSs section by section, see our articles how to read a safety data sheet and, for the details of the regulation, the chemical substances regulation.
Dyehouse steam risk and pressurised dyeing vessels
A dyehouse works with steam and hot liquids. Desizing and scouring baths, jet and overflow dyeing machines, hot washing machines and the steam distribution line all carry a risk of burns. High-temperature (HT) dyeing machines keep the dye bath above 100 °C under pressure.
The vessels of dyeing machines are listed separately among pressure vessels in Annex III, Table 1 of the Regulation on Work Equipment: unless standards set a shorter interval, their periodic inspections are carried out at least once a year against the criteria in TS EN ISO 11111-1, TS EN ISO 11111-7 and TS EN 764-7. A hydrostatic test at operating pressure is carried out at each inspection, and repeated at test pressure at least every three years. The boiler supplying the steam will itself be inspected by an equipment inspection body from 1 January 2027; details are in our article on steam boiler safety.
Check the following points on site:
- Opening the lid: The dyeing vessel lid must not be opened until internal pressure and temperature have fallen to a safe level. The lid lock and pressure release arrangement must work and must not be bypassed.
- Sampling: Samples are taken from the bath using the machine's sampling device and according to the manufacturer's instructions; not by easing the lid open.
- Steam line: Pipes and valves that employees may touch are insulated; steam leaks are put on the maintenance list rather than patched by stuffing a rag under the valve.
- Adding chemicals: Adding chemicals to a hot bath carries a risk of splashing, boiling and foaming; dosing tanks and closed addition are preferred.
- Energy isolation before maintenance: Before entering the vessel or working on the pump, steam, water and electricity are isolated, pressure is released, and lockout and tagout are applied.
Dyehouse slip risk and wet floors
The floor of a dyehouse is almost never dry: bath overflowing from machines, hose water, foam and chemical residues make the floor slippery. Annex 1 of the Regulation on Health and Safety Measures in Workplace Buildings and Annexes requires floors to be sound, dry and as far as possible even, non-slip and free of level differences. In a department with wet processes, this means in practice:
- The floor should slope so that water drains into grated drainage channels; gratings should be complete and flush with the floor.
- Non-slip coatings should be renewed as they wear and should be chemical-resistant.
- Hoses should be wound onto reels when not in use and not left on walkways.
- Machine overflows should be recorded as maintenance issues; a machine that constantly overflows is a sign of a fault.
- Employees should be given chemical-resistant safety shoes or boots with non-slip soles.
- Places where wet floors and hot liquid meet, such as machine discharge points, should be marked and pedestrian routes kept away from them.
Maintenance and cleaning: overlooked jobs
A significant share of risky work in a dyehouse is done not during production but during machine cleaning and maintenance. Because these jobs are not in routine production instructions, they should be addressed separately in the risk assessment:
- Machine washing and descaling: The acid or alkaline cleaning programmes of dyeing machines may use more concentrated chemicals than in production. The SDS of the cleaning chemical should also be on file, and which chemical the programme uses should be written on the machine.
- Entry into tanks and vessels: The inside of chemical preparation tanks and dyeing vessels is a confined space. Before entry, the tank is emptied, washed and ventilated, the atmosphere is measured, all energy and supply lines are isolated and locked out, and a written work permit is issued. An attendant stays outside.
- Filter and strainer cleaning: Strainers clogged with fibre and dye residue are removed from hot and pressurised lines. The strainer cover must not be opened until the line has cooled and been depressurised.
- Wastewater treatment: Acid and caustic are dosed to neutralise dyehouse wastewater; the treatment section is also part of the chemical risk assessment.
Workplace measurements and health surveillance
Measurements of chemical exposure, noise and hot environments in the dyehouse are inputs to the risk assessment. We plan these measurements and the necessary medical tests with authorised laboratories and health institutions; the results are entered into the risk assessment. In health surveillance, the workplace physician pays particular attention to respiratory complaints of employees in the weighing and dissolving section and to skin findings in employees in contact with chemicals. Legislation does not fix the frequency of tests such as lung function tests; the physician sets it according to the risk. In the hazardous class, periodic examinations are repeated at least every 3 years.
A short checklist for the dyehouse
| Area | Check |
|---|---|
| Chemical store | Are SDSs current and in Turkish; are acids, oxidisers and hypochlorite kept separate? |
| Colour kitchen | Is local exhaust working; is weighing dust spreading? |
| Dyeing vessels | Is the last periodic inspection report less than 12 months old; does the lid lock work? |
| Steam line | Is insulation complete; are leaks recorded? |
| Floor | Are drainage gratings in place; is the non-slip coating worn? |
| Emergency | Are the eyewash and emergency shower working; is a spill kit ready? |
For the steps of responding to a chemical spill, see our article on responding to chemical spills. You can enter periodic inspection and measurement dates into the OHS calendar. For an assessment specific to your dyehouse, see our risk assessment and OHS specialist services, and for other sector-specific topics, our textiles and Nilüfer OSGB pages.
Frequently Asked Questions
Which hazard class is a dyehouse in?
In the list renewed in 2025, textile bleaching and dyeing (13.30.01) is in the hazardous class; it was very hazardous in the 2012 list. To confirm your class, assess the NACE code in your SGK workplace registration together with the main activity at the workplace.
Are dyeing vessels subject to periodic inspection?
Yes. The vessels of dyeing machines are listed among pressure vessels in Annex III and are inspected at least once a year unless standards set a shorter interval. The inspection is carried out by an authorised person registered in EKİPNET, the Ministry's register of authorised inspectors.
What PPE should be used in a dyehouse?
It is chosen according to the chemical and is specified in section 8 of the SDS: usually chemical-resistant gloves, a face shield or goggles, an apron and shoes with non-slip soles. If local exhaust is not enough during weighing of powdered dyes, suitable respiratory protection is added. PPE comes after technical measures.
Is an eyewash mandatory in a dyehouse?
Where corrosive chemicals are used, the means of emergency response to splashes to the eyes and skin are determined by the risk assessment and the first aid measures in the SDS. We recommend keeping an easily accessible, regularly tested eyewash near points where caustic and acids are handled.
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.