Heated humidifiers used in combination with heated-wire breathing systems - risk of oxygen-fuelled fire

(Various manufacturers) Risk if alarms are ignored or damaged breathing systems are used. (MDA/2014/020)

CAS Deadlines

Action underway: 18 June 2014,  Action complete: 02 July 2014

Note: These deadlines are for all affected staff to be made aware of the issue and amended procedures to be put in place.


Heated humidifiers used in combination with heated-wire breathing systems.

Various manufacturers.


Risk of oxygen-fuelled fire if:

  • alarms are ignored
  • damaged breathing systems are used.

The MHRA is aware of a fire caused by a damaged breathing system being used with an elevated oxygen concentration. The humidifier alarmed but the user silenced it and did not take any action.


Ensure users respond to all alarms immediately.

If a humidifier indicates there is a problem with the breathing system, follow the manufacturer’s instructions for checking and replacing it.

If a breathing system is damaged, eg jammed in a bed rail, run over by a trolley, or if it comes apart, replace it.

Action by

All staff involved in the use of heated-wire breathing systems.


This MDA has been sent to:

  • Care Quality Commission (CQC) (headquarters) for information
  • Clinical commissioning groups (CCGs)
  • HSC trusts in Northern Ireland (chief executives)
  • Local authorities in Scotland (equipment co-ordinators)
  • NHS boards and trusts in Wales (chief executives)
  • NHS boards in Scotland (equipment co-ordinators)
  • NHS England area teams for information
  • NHS trusts in England (chief executives)

Onward distribution

Please bring this notice to the attention of relevant employees in your establishment. 
Below is a suggested list of recipients.


CAS and SABS (NI) liaison officers for onward distribution to all relevant staff including:

  • Adult intensive care units
  • Anaesthesia, directors of
  • Anaesthetic medical staff
  • Anaesthetic nursing staff
  • Anaesthetists
  • Clinical governance leads
  • Hospital at home units
  • Intensive care medical staff/paediatrics
  • Intensive care nursing staff (adult)
  • Intensive care nursing staff (paediatric)
  • Intensive care units
  • Intensive care, directors of
  • Operating department practitioners
  • Paediatric intensive care units
  • Risk managers
  • Special care baby units
  • Theatre managers
  • Theatre nurses
  • Theatres

Independent distribution

Establishments registered with the Care Quality Commission (CQC) (England only)

This alert should be read by:

  • Hospitals in the independent sector

Please note: CQC and OFSTED do not distribute these alerts. Independent healthcare providers and social care providers can sign up to receive MDAs directly from the Department of Health’s Central Alerting System (CAS) by sending an email to: safetyalerts@dh.gsi.gov.uk and requesting this facility.


If you have any comments or feedback on this Medical Device Alert please email us at: dts@mhra.gov.uk


If you are in England, please send enquiries about this notice to the MHRA, quoting reference number MDA/2014/020 or 2013/011/008/401/015.

Technical aspects

Ian Sealey or Louise Mulroy
Medicines & Healthcare Products Regulatory Agency
Floor 4
151 Buckingham Palace Road
London SW1W 9SZ
Tel:    020 3080 6691/7344
Fax:  020 8754 3965

Email: ian.sealey@mhra.gsi.gov.uk or louise.mulroy@mhra.gov.uk

Clinical aspects

Mark Grumbridge
Medicines & Healthcare Products Regulatory Agency
Floor 4
151 Buckingham Palace Road
London SW1W 9SZ
Tel: 020 3080 7128
Fax: 020 8754 3965

Email: mark.grumbridge@mhra.gov.uk

How to report adverse incidents

Please report via our website: Reporting adverse incidents involving medical devices
Further information about CAS can be found on the CAS website 

Northern Ireland

Alerts in Northern Ireland will continue to be distributed via the NI SABS system.

Enquiries and adverse incident reports in Northern Ireland should be addressed to:

Northern Ireland Adverse Incident Centre
Health Estates Investment Group
Room 17
Annex 6
Castle Buildings, Stormont Estate
Dundonald BT4 3SQ
Tel:02890 523 704
Fax:02890 523 900



How to report adverse incidents in Northern Ireland

Please report directly to NIAIC, further information can be found on the NIAIC website

Further information about SABS can be found on the SABS website


All requests regarding return, replacement or modification of the devices mentioned in this alert should be directed to the relevant supplier or manufacturer.

Other enquiries and adverse incident reports in Scotland should be addressed to:

Incident Reporting and Investigation Centre
NHS National Services Scotland
Gyle Square
1 South Gyle Crescent
Edinburgh EH12 9EB
Tel:    0131 275 7575
Fax:  0131 314 0722

Email: nss.iric@nhs.net

Incident Reporting and Investigation Centre 


Enquiries in Wales should be addressed to:

Improving Patient Safety Team
Medical Directorate
Welsh Government
Cathays Park
Cardiff CF10 3NQ

Email: improvingpatientsafety@wales.gsi.gov.uk

Download documents

Medical Device Alert: Heated humidifiers used in combination with heated-wire breathing systems - Various manufacturers (MDA/2014/020) (137Kb)

Published 17 December 2014