Four organisations offer examinations as part of the OHTA international training scheme and qualifications framework.
Approved Training Providers can book examinations with two of them:
- BOHS (any Approved Training Provider, any W module)
- SAIOH (Southern African Approved Training Providers, W201 only).
More information is available below.
Examining Bodies
American Industrial Hygiene Association (AIHA)
W201 Module
AIHA is authorised to act as examiner for the W201 module as part of its online, self-study Basic Principles of Occupational Hygiene course .
AIHA is a member association of OHTA.
British Occupational Hygiene Society (BOHS)

BOHS is the only awarding and examining body for OHTA W500 series modules and the International Certificate in Occupational Hygiene (ICertOH). It is also an authorised examining body for the OHTA W201 module. BOHS is a member association of OHTA.
OHTA Approved Training Providers book examinations directly with BOHS. For more information contact qualifications@bohs.org
W Series Modules
BOHS Examination Fee
The BOHS examination fee for OHTA W series modules in 2021 is £100.00 per student. Full details of the BOHS examination fees are available on the BOHS website here.
OHTA Course Levy
In addition to the BOHS examination fee, there is an OHTA course levy of £40.00 per student. This is collected by BOHS on behalf of OHTA at the same time that BOHS collects the examination fee. The OHTA course levy is not charged for resits.
Total cost per student
- £100.00 BOHS Examination Fee
- £40.00 OHTA Course Levy
- TOTAL = £140.00
International Certificate in Occupational Hygiene (ICertOH)
All information about the entry requirements, application process and fees can be found on the BOHS website here.
Southern African Institute for Occupational Hygiene (SAIOH)
W201 Module
SAIOH is authorised to act as examiner for the W201 module for Southern African based Approved Training Providers in Southern Africa. W201 is the entry level assessment for SAIOH's assistant level registration.
Information on how to order W201 examinations, including the fee, is available on the SAIOH website here.
SAIOH is a member association of OHTA.
Workplace Health Without Borders (WHWB)
W201 Module
WHWB is authorised to act as examiner for the W201 module as part of its own W201 training activity.
WHWB is a member association of OHTA.