OHS When Working with Subcontractors: Who Is Responsible?

What is the principal employer–subcontractor relationship?

A maintenance company, a cleaning firm, a canteen operator, an assembly team or the electrical subcontractor on a construction site: when employees of more than one employer are present in a workplace at the same time, the question of subcontractor OHS responsibility arises. In this article we explain how duties are divided in the legislation, where joint responsibility arises and what should be written into the contract.

Under Art. 2 of Labour Law No. 4857, the principal employer–subcontractor relationship is the relationship established with an employer who takes on work from another employer in ancillary work related to the production of goods or services at the workplace, or in part of the main work requiring expertise for reasons of the business, the nature of the work and technology, and who employs its workers only on the work taken on at that workplace. Outside this exception, the main work may not be split up and given to a subcontractor; otherwise the relationship may be deemed collusive, and the subcontractor's workers are treated as the principal employer's workers from the outset.

Subcontractor OHS responsibility: each employer is responsible for its own employees

Law No. 6331 defines the employer as the person "employing employees". A subcontractor is also an employer; all the basic obligations of Law No. 6331 therefore apply to it too:

• It appoints an OHS specialist and a workplace physician for its own employees; if required, it also appoints other health personnel (DSP).
• It carries out, or has carried out, a risk assessment for the work it performs.
• It provides OHS training to its employees, has health surveillance carried out and provides PPE.
• It records and reports its own employees' work accidents.

This is where the "subcontractor OSGB" question comes from: the subcontractor obtains OHS services in-house or from an OSGB (joint health and safety unit) of its own choosing; the contract and appointment are made in the subcontractor's own name and approved on ISG-KATİP (the Ministry's online OHS registration system). The subcontractor's appointment obligation does not disappear because the principal employer's specialist looks after the subcontractor's employees.

The principal employer remains responsible for its workplace as a whole. The legislation gives it three roles: informing, supervising and coordinating.

Division of OHS duties between principal employer and subcontractor

The OHS committee row leads to four different outcomes depending on headcount. Under Art. 4 of the Regulation on OHS Committees, in a relationship lasting more than six months:

• If each has 50 or more employees, each sets up its own committee; the principal employer ensures coordination.
• If only the principal employer has 50 or more employees, the principal employer sets up the committee; the subcontractor appoints an authorised representative for coordination.
• If only the subcontractor has 50 or more employees, the subcontractor sets up the committee; the principal employer appoints a representative to this committee.
• If each has fewer than 50 but together they exceed 50, a joint committee is formed with the principal employer running the coordination.

Primary texts of the regulations named in the table: Risk Assessment Regulation, Regulation on Emergencies, 2026 Training Regulation and Physician and DSP Regulation.

What does joint liability mean in OHS?

When "subcontracted work safety" is discussed, the most frequently asked question is whether the principal employer is responsible for the subcontractor's mistakes. There are two separate bases in the legislation:

• Law No. 4857, Art. 2/6: The principal employer is jointly responsible with the subcontractor towards the subcontractor's workers for obligations arising from the Labour Law, the employment contract or a collective agreement to which the subcontractor is a party, in relation to that workplace.
• Law No. 5510, Art. 12: The principal employer is jointly responsible with the subcontractor for the obligations the social security law places on the employer.

OHS legislation, however, defines responsibility not with a general "joint responsibility" sentence but subject by subject, as in the table above. How fault is divided in an accident is decided by experts and the court according to the circumstances of the specific case. The practical lesson for the principal employer is this: a principal employer that cannot show with documents that it carried out its supervision and coordination duty cannot separate itself from the consequences of the subcontractor's deficiencies on site.

What should be written into the contract

We recommend including the following OHS clauses in the service or works contract with the subcontractor:

1. OHS services: The subcontractor presents the ISG-KATİP record of its specialist and physician appointments before work begins.
2. Risk assessment: A copy of the risk assessment specific to the work is delivered before work begins and updated as the work changes.
3. Training and health: A list of employees' OHS training certificates, fitness-for-work reports and, where necessary, vocational training certificates.
4. Equipment: Periodic inspection reports for work equipment brought on site and safety data sheets for chemicals to be used.
5. Site rules: Attendance at site induction training, work requiring a permit, PPE rules and the possibility of stopping work in case of non-compliance.
6. Reporting: Accidents, near misses and dangerous situations are reported to the principal employer on the same day.
7. Coordination: Meeting frequency, contact persons and who manages what in an emergency.
8. Sub-subcontractors: If part of the work is to be given to another company, prior written permission and application of the same terms to it.

On site: induction, work permits and supervision

However good the contract, a clause that is not applied on site is of no use at an inspection. Set up the following arrangement on the principal employer's side:

• Entry control: A subcontractor employee receives short induction training on first entering the facility; training, identity and document checks are recorded.
• Work permits: Work such as hot work, work at height, confined spaces and electrical work begins with a written permit. We explain how to set up the system in our article on the permit-to-work system.
• Supervision: The principal employer's specialist observes the subcontractor's practice on site at regular intervals and reports findings in writing.
• Information flow: The subcontractor's risk assessment is entered in the principal employer's risk assessment; shared risks are explained to both parties' employees.

In OIZs (organised industrial zones) in Bursa and the surrounding provinces, maintenance shutdowns and annual overhauls are usually periods when several subcontractors enter the site at the same time; preparing a separate coordination plan for these periods is particularly useful. For how to report a subcontractor employee's accident and situations that count as a work accident, see our article on what counts as a work accident, and for the general steps of risk assessment, our risk assessment guide.

For construction sites where several companies work, our construction sector page provides guidance, and for fines the OHS administrative fines tool. In our OHS specialist services, we organise subcontractor induction training, the document checklist and coordination minutes on behalf of the principal employer.

Frequently Asked Questions

Does the subcontractor have to appoint its own OHS specialist?

Yes. The subcontractor is also an employer under Law No. 6331 and appoints a specialist and physician for its own employees. It can obtain the service in-house or from an OSGB of its choice; the principal employer's specialist does not meet this obligation.

Who reports a subcontractor employee's work accident?

Under Art. 13 of Law No. 5510, the notification is made by the employer employing the insured person; in this case, the subcontractor. However, under Art. 12 of Law No. 5510, the principal employer is jointly responsible with the subcontractor for the obligations the Law places on the employer. Write into the contract that the accident is also reported to the principal employer on the same day.

Does the principal employer have to approve the subcontractor's risk assessment?

The Regulation gives a duty of "supervision and coordination", not "approval". The principal employer receives a copy of the subcontractor's risk assessment, integrates it with its own work, monitors whether measures are implemented and ensures that non-conformities are corrected.

Does a cleaning or catering company also count as a subcontractor?

Such companies, which continuously carry out ancillary work at the workplace, are subcontractors as long as they fit the definition in Art. 2 of Law No. 4857. They meet their own OHS obligations; the principal employer includes them in the emergency plan, induction information and coordination.