In brief
In a workplace in the very hazardous class, a class A OHS specialist, a workplace physician and, with 10 or more workers, other health personnel (DSP) are assigned. Basic training is at least 16 hours and is repeated every year for at least 8 hours; periodic examinations are carried out every year; the risk assessment and emergency plan are renewed at least every 2 years. The administrative fine for the same breach is also increased up to three times in the very hazardous class.
How is the very hazardous class determined?
Very hazardous workplace obligations depend on the class the workplace receives in the OHS Hazard Classes List (Communiqué Annex 1) according to its NACE code. The class is determined by the main activity carried out at the workplace; if there is more than one main activity, the higher class applies. Annex 1 was completely renewed on 13 March 2025 with 6-digit NACE Rev.2.1 codes; matches made with the old 2012 codes should no longer be used.
Verified example codes in the very hazardous class in the construction sector are: 43.12.00 site preparation, and 43.22.06 and 43.22.07 HVAC installation and maintenance. In industry, 25.53.03 laser cutting of metals and 25.51.01 nickel plating of metals are in this class. The class of some activities changed with the new list; for example, textile bleaching and dyeing (13.30.01) was very hazardous in the 2012 list but is now hazardous.
A change of main activity is notified to the Ministry within 1 month; if the class changes, the obligations required by the new class are met within 90 days. We explained how to find your code in our article on how to find your hazard class.
Very hazardous workplace obligations: comparison table
The table below shows at a glance how the very hazardous class differs from the other two classes. The columns on the right are for comparison; for details of the hazardous and less hazardous classes, see our articles on hazardous class obligations and less hazardous class obligations.
| Obligation | Very hazardous | Hazardous | Less hazardous |
|---|---|---|---|
| Specialist certificate class | A | At least B | At least C |
| Specialist time (per worker, monthly) | 40 min | 20 min | 10 min |
| Physician time (per worker, monthly) | 15 min | 10 min | 5 min |
| DSP | Mandatory with 10 or more workers | None | None |
| Basic training | At least 16 hours | At least 12 hours | At least 8 hours |
| Refresher training | Every year, at least 8 hours | Every 2 years | Every 3 years |
| Periodic examination | Every year | At least every 3 years | At least every 5 years |
| Risk assessment renewal | At least every 2 years | At least every 4 years | At least every 6 years |
| Emergency plan renewal | At least every 2 years | At least every 4 years | At least every 6 years |
| First aiders | 1 per 10 workers | 1 per 15 workers | 1 per 20 workers |
| Support staff (per team) | At least 1 for up to 30 workers | At least 1 for up to 40 workers | At least 1 for up to 50 workers |
Class A specialist, workplace physician and DSP: calculating the time
Under Art. 8/5 of Law No. 6331, the OHS specialist assigned to a workplace in the very hazardous class must hold a class A certificate. An assignment made with a class B or C specialist does not meet the obligation in this class. Art. 6 requires other health personnel to be assigned in addition to the specialist and physician in very hazardous workplaces with 10 or more workers; if a full-time physician is assigned, a DSP is not required.
The minimum monthly times are in the OHS Specialists Regulation and Art. 12 of the Workplace Physicians and DSP Regulation. DSP time varies with headcount: 10 min for 10–49 workers, 15 min for 50–249 workers and 20 min for 250 or more workers. One full-time specialist is assigned for every 250 workers and one full-time physician for every 750 workers.
Example: a construction workplace with 60 workers in the very hazardous class
- Specialist: 60 × 40 min = 2,400 min, i.e. 40 hours a month, holding a class A certificate.
- Physician: 60 × 15 min = 900 min, i.e. 15 hours a month.
- DSP: since it falls in the 50–249 range, 60 × 15 min = 900 min, i.e. 15 hours a month.
- First aiders: 60 / 10 = at least 6 people.
- Support staff: at least 2 for each of the firefighting, rescue and protection teams, at least 6 people in total.
- Employee representatives: 2 people in the 51–100 worker range (Law 6331 Art. 20).
You can do the calculation with your own headcount in the OHS obligation calculator. We explained the logic of the times in detail in our article on workplace physician and specialist working times.
Training: 16 hours of basic training and annual refreshers
The new training regulation, published in the Official Gazette on 2 April 2026, sets the following rules for the very hazardous class:
- Induction training: for everyone, including apprentices and interns, before starting work, at least 2 hours, face to face and practical. It does not count towards basic training time and is documented in a written record.
- Basic training: within 3 months of starting work at the latest, at least 16 lesson hours. At least 4 hours of this are devoted to job- and workplace-specific risks, and this section is delivered face to face.
- Refresher training: every year, at least 8 hours.
- Examination: at least 60 points out of 100.
Vocational training is also a separate obligation. In hazardous and very hazardous work, people who will do the jobs listed in Annex 1 of the vocational training regulation must document that they have received this training before being hired. You can find the changes to the training regime in our article on the new OHS training regulation.
Health surveillance: fitness-for-work report and annual examination
Under Law 6331 Art. 15, in hazardous and very hazardous work a worker cannot start without a fitness-for-work report. The report is obtained from the workplace physician. In the very hazardous class, periodic examinations are carried out every year; for child, young and pregnant workers they are at least every 6 months, and the physician can shorten these intervals. The legislation does not set a fixed list of tests; the workplace physician decides according to the risk.
The DSP is the on-site supporter of this programme: together with the physician, they track the examination schedule and health records and pass their findings and recommendations to the workplace physician. We carry out these duties as part of our workplace nursing service.
Risk assessment, emergencies and the OHS committee
- The risk assessment is renewed at least every 2 years. In situations such as relocation, new equipment, a change in production method, a workplace accident, an occupational disease or a near miss, it is updated without waiting for the period to expire. On a construction site, hazards change as the work stage changes.
- The emergency plan is renewed at least every 2 years; a drill is held at least once a year and a drill form is completed.
- An OHS committee is set up in workplaces with 50 or more workers where continuous work lasting more than six months is carried out (Law 6331 Art. 22). A site with 60 workers that will run for a year falls within this scope. We explained how to set up the committee in our article on how to set up an OHS committee.
Increased fines: why is the same breach more expensive?
Law 6331 Art. 26/3 increases administrative fines according to headcount and hazard class. In the very hazardous class, the increase is 50% for fewer than 10 workers, 100% for 10–49 workers and 200% for 50 or more workers. The 2026 amounts for the example workplace with 60 workers:
| Breach | Base amount | Increased amount (×3) |
|---|---|---|
| Not carrying out a risk assessment | 66,725 TL | 200,175 TL; a further fine each month the breach continues |
| Not assigning a specialist or physician | 111,263 TL per person | 333,789 TL per person; each month |
| Not assigning a DSP | 55,597 TL | 166,791 TL; each month |
Under Art. 26/5, no increase is applied to fines calculated per worker (such as 8,980 TL per worker for not providing training and 22,194 TL per worker for not carrying out health surveillance); but because they are multiplied by the headcount, the total is still high. You can calculate your own amount with the OHS administrative fines tool.
Order of implementation for the first 30 days on site
If you are opening a new site or workplace in the very hazardous class, follow this order:
- Verify the NACE code and class; estimate the headcount.
- Have the contract for the class A specialist, physician and, if required, the DSP approved on İSG-KATİP (the Ministry's online OHS registration system) before work starts.
- Prepare a fitness-for-work report and an induction training record for each worker; check vocational training certificates.
- Prepare the first risk assessment and emergency plan; assign first aiders and support staff in writing.
- Spread the basic training schedule over the first 3 months; if you will exceed 50 workers, plan the committee.
We plan these steps together with you through our OHS specialist services; for site-specific notes, see our construction sector page.
Frequently Asked Questions
Can a class B specialist work in a very hazardous workplace?
No. Under Law 6331 Art. 8/5, the specialist in workplaces in the very hazardous class must hold a class A certificate.
When is a DSP mandatory in a very hazardous workplace?
It is mandatory in very hazardous workplaces with 10 or more workers. If a full-time workplace physician is assigned, a DSP does not need to be assigned.
How many hours of training are required in the very hazardous class?
Basic training is at least 16 lesson hours and is completed within 3 months of starting work at the latest. At least 4 hours of this are devoted to job-specific risks and delivered face to face. Refresher training is every year, at least 8 hours; in addition, at least 2 hours of induction training are given before starting work.
How often are periodic examinations carried out in a very hazardous workplace?
Every year. For child, young and pregnant workers they are at least every 6 months; the workplace physician may shorten the interval if necessary.
A certified specialist matched to your hazard class: site inspections, approved logbook, training plan, annual plan and report follow-up.
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.