OHS Obligations of Workplaces in the Hazardous Class

What does the hazardous class mean, and how do you find it?

Hazardous class workplace obligations mean documents renewed more often, longer training and a more highly qualified specialist than in the less hazardous class; and the starting point for all of them is determining the class correctly. A workplace's hazard class is the class that corresponds to the NACE code in its SGK registration and appears in the Annex 1 list of the Communiqué on Workplace Hazard Classes Relating to Occupational Health and Safety. Under the Communiqué, what counts is the main activity carried out at the workplace; if there are several main activities, the higher class applies. Annex 1 was completely renewed on 13 March 2025 with six-digit codes according to NACE Rev.2.1; you need to update assessments made under the old 2012 codes.

The hazardous class is very common in Bursa's industrial structure. Examples verified from the 2025 list:

25.53.01 Machining and welding work: hazardous
29.32.20 Manufacture of parts and accessories for motor vehicles: hazardous
13.20.16 Cotton weaving: hazardous
31.00.01 Manufacture of bedroom, kitchen and similar furniture: hazardous

A sub-activity in the same sector may have a different class: for example, 25.53.03 laser cutting of metals is very hazardous. To verify your code, see our article how to find your hazard class. A workplace whose class changes fulfils the requirements within 90 days. For a comparison with the less hazardous class, our article on less hazardous workplace obligations provides guidance.

Specialist and physician: class B certificate and the minutes calculation

Under Art. 8/5 of Law No. 6331, the OHS specialist assigned to a workplace in the hazardous class must hold at least a class B certificate; a class A specialist may also serve, but a class C specialist may not. The obligation to assign other health personnel (DSP) applies only to the very hazardous class.

The minimum monthly times per employee are 20 minutes for the specialist and 10 minutes for the physician. One full-time assignment is made for every 500 employees for the specialist and every 1,000 employees for the physician; the minutes calculation applies to the remaining employees. Examples:

60 employees: specialist 60 × 20 = 1,200 minutes (20 hours), physician 60 × 10 = 600 minutes (10 hours) per month.
650 employees: specialist 1 full-time + 3,000 minutes (50 hours) for the remaining 150 employees; physician 650 × 10 = 6,500 minutes (about 108 hours) per month.

You can see your own figures in the OHS obligation calculator, and find the details of the calculation logic in our article on physician and specialist working times. If you receive services from an OSGB, the contract is prepared on ISG-KATİP, the Ministry's online OHS registration system, and both parties approve it within 5 days at the latest; work cannot begin under an unapproved assignment.

Table of hazardous class workplace obligations

Obligation	Rule in the hazardous class	Basis
OHS specialist	At least class B; 20 min/employee per month; 1 full-time per 500 employees	Law 6331 Art. 8/5; OHS Specialists Regulation Art. 12
Workplace physician	10 min/employee per month; 1 full-time per 1,000 employees	Physicians Regulation Art. 12
Other health personnel	Not required	Law 6331 Art. 6
Risk assessment	At least every 4 years and upon changes	Risk Assessment Regulation
Emergency plan	Every 4 years; drill at least once a year	Emergencies Regulation
Support staff	At least 1 for each of the firefighting, rescue and protection teams for up to 40 employees	Emergencies Regulation Art. 11
First aider	1 per 15 employees	First Aid Regulation
Pre-employment examination	Work cannot begin without a fitness-for-work report	Law 6331 Art. 15
Periodic examination	At least every 3 years; the physician may shorten this	Physicians Regulation Art. 9
Induction training	At least 2 hours, face to face, before starting work	Training Regulation 2026 Art. 7
Basic training	12 class hours, within the first 3 months; at least 3 hours for topic group 4, face to face	Arts. 8 and 13
Refresher training	Every 2 years, at least 8 hours	Art. 14
Vocational training certificate	Before hiring, for jobs in Annex 1 of the vocational training regulation	Law 6331 Art. 17
OHS committee	With 50 or more employees and continuous work lasting more than 6 months	Law 6331 Art. 22
Employee representative	1 for 2–50 employees, 2 for 51–100, 3 for 101–500	Law 6331 Art. 20

Training durations are based on the OHS training regulation published in Official Gazette No. 33212 of 2 April 2026. Distance learning is possible only for the first three topic groups; topic group 4, covering risks specific to the job and workplace, is delivered face to face in the hazardous class. For a summary of the changes, see our article on the new OHS training regulation.

Annual calendar for a workshop with 60 employees

Sample business: a workshop in Bursa doing machining and welding (25.53.01), with 60 people working a single shift. The minimum figures for this business are: 20 hours of specialist and 10 hours of physician service per month, 4 first aiders (60 / 15), 2 support staff for each of the firefighting, rescue and protection teams (60 / 40, rounded up), 2 employee representatives and, since the 50-employee threshold is exceeded, an OHS committee. The committee meets at least once a month; however, in hazardous workplaces the committee may set this period at two months.

You can plan the annual workflow as follows:

January: The annual work plan prepared jointly by the specialist and physician is submitted for the employer's approval; the dates of training, examinations, measurements and periodic inspections during the year are included in this plan. For preparation, see our article on the annual work plan.
February–March: Periodic inspections under Annex III are carried out on the forklift, compressor tank, press, welding machines and electrical installation.
April: An emergency drill is held, a drill report is prepared and the plan is corrected if necessary.
May: Noise and welding fume measurements are planned with authorised laboratories and health institutions at the interval set by the risk assessment.
June: At least 8 hours of refresher training is given to employees whose last refresher training was 2 years ago.
September: Employees whose periodic examination is due are examined; in the hazardous class each employee's examination is renewed at least every 3 years, and at least every 6 months for those under 18 and pregnant employees.
November: The risk assessment is reviewed with the year's accident, near miss and measurement results; if the 4-year renewal date is approaching, new work is started.
December: The annual evaluation report prepared jointly by the physician and specialist is completed.

A fixed sequence is also followed for every new employee: pre-employment examination and fitness-for-work report, at least 2 hours of induction training, a check of the vocational training certificate if required, and 12 hours of basic training within the first 3 months. You can enter the dates in the OHS calendar tool and link them to reminders.

Common mistakes in the hazardous class

Applying the times for the less hazardous class: Giving 8 hours of basic training, scheduling periodic examinations every 5 years or renewing the risk assessment every 6 years.
Continuing with a class C specialist: Workplaces whose class rose from less hazardous to hazardous with the 2025 list must switch to at least a class B specialist within 90 days.
Delivering topic group 4 remotely: If job-specific risks are not delivered face to face in the hazardous class, the training is considered incomplete.
Setting up the committee but not convening it: A committee without meeting minutes and a decision book shows during an inspection that it does not actually function; failing to implement committee decisions is also subject to separate penalties.
Forgetting subcontractor employees: The training and health reports of subcontractor personnel working at the same workplace should also be checked.

How do fines increase in the hazardous class?

Under Art. 26/3 of Law 6331, administrative fines in hazardous class workplaces are increased by 25% for fewer than 10 employees, 50% for 10–49 employees and 100% for 50 or more employees. No increase is applied to fines calculated per employee (Art. 26/5). As our sample workshop has 60 employees:

If no risk assessment has been carried out, the base amount of 66,725 TL becomes 133,450 TL with the 100% increase; a further fine is applied every month the violation continues.
If no OHS specialist or workplace physician has been assigned, the base amount of 111,263 TL per person becomes 222,526 TL with the 100% increase and is repeated every month.
For 20 employees who have not been trained, the fine is 8,980 TL per employee, giving 179,600 TL without any increase.

You can see the amounts for your own workplace in the administrative fine calculator. For workplaces in the hazardous class, we handle the assignment of the specialist and physician, together with the training and examination calendar, as part of our OHS specialist and workplace physician services. For risks specific to the metal sector, see our metal and machinery page.

Frequently Asked Questions

Can a class C specialist work in the hazardous class?

No. Under Art. 8/5 of Law 6331, at least a class B certificate is required in the hazardous class. A class A specialist may serve; a class C specialist may only work in less hazardous workplaces.

How often is the periodic examination carried out in the hazardous class?

At least every 3 years. The workplace physician shortens the interval if deemed necessary; for children, young workers and pregnant employees, the examination is repeated at least every 6 months.

How long is training in the hazardous class?

At least 2 hours of induction training is given before starting work, followed by 12 class hours of basic training within the first 3 months. Refresher training is every 2 years and at least 8 hours.

Are other health personnel mandatory in the hazardous class?

No. The obligation to assign DSP applies to very hazardous workplaces with 10 or more employees. In the hazardous class, assigning a specialist and a physician is sufficient.