Assess the work
Document the source, treatment volume, materials, ventilation and who is responsible.
Controlled professional use
Protect people first. Then protect the process.
Ozone is hazardous to health. A responsible treatment plan controls access, operation, ventilation and re-entry—and records who is accountable at every step.
Five-part framework
From assessment to documented hand-back.
This framework supports professional planning but does not replace the product instructions, a COSHH assessment or competent advice.
Control access
Remove people, animals and plants where the procedure requires an unoccupied space. Isolate and sign the area.
Operate to procedure
Use suitable equipment, trained operators and a site-specific risk assessment rather than a generic timer setting.
Ventilate and verify
After treatment, ventilate and use suitable measurement to support the re-entry decision.
Record the outcome
Keep the operating details, monitoring results, hand-back time and any exceptions with the job record.
HSE workplace guidance
The Health and Safety Executive identifies ozone as hazardous to health and requires suitable assessment and controls where workplace exposure may occur. EH38 states a workplace exposure limit of 0.2 ppm averaged over 15 minutes.
Read HSE EH38: Ozone — health hazards and control measures
In-situ generated biocides
Where ozone is generated and used for a biocidal purpose, the active substance and intended use sit within the relevant biocides framework. Product positioning and customer claims must reflect the applicable authorisation status.
Read HSE guidance on in-situ generation
Odour-treatment evidence
The Environment Agency notes that the effectiveness of indoor reactive treatments such as ozone can be difficult to monitor and requires relevant assessment before acceptance in regulated odour-abatement contexts.
Read Environment Agency odour-management guidance
Common questions
What exposure limit does HSE state for ozone?
HSE EH38 states a workplace exposure limit of 0.2 ppm in air averaged over a 15-minute reference period. Employers must also complete a suitable and sufficient COSHH assessment where exposure is likely.
Is elapsed time enough to decide re-entry?
No. Decay depends on the space, materials, temperature, ventilation and other conditions. Follow the product procedure and use suitable monitoring where specified.
Does this page replace a risk assessment?
No. It is general information. The employer, operator and site dutyholders remain responsible for a suitable site- and task-specific assessment and controls.
Application support
Need to specify equipment within a controlled procedure?
Tell us about the space, odour source and operating constraints. We’ll help define a responsible equipment and hire or purchase route.