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Personal Protective Equipment (PPE) and Practices and Influenza Pandemic preparedness.

Introduction

This advice has been prepared by the Department of Labour in consultation with a number of medical, scientific and health and safety experts. It represents the Department’s best information about the likely impact of an influenza pandemic on workers and workplaces and provides a wider reference source for those seeking to understand the rationale behind some of the key protection methods.

It provides general information and a risk management framework to other more specific information on this website, particularly:

The advice will be updated as appropriate through the Department’s web site www.dol.govt.nz and readers should consult this periodically or register to receive automatic alerts.

Summary

The requirement for PPE needs to be determined through a hazard management approach and to be clearly set in the wider context of the hierarchy of controls – eliminate, isolate, minimise – as set out in the Health and Safety in Employment Act.

To be effective PPE has to be carefully selected and properly used, which implies that training must be given as specified in the relevant standard. PPE is only a partial solution to pandemic preparedness and its limitations in terms of performance and useability should be clearly recognised.

Contents

Glossary

  1. Occupational groups and settings to be considered
  2. Structure of advice and its place in the wider picture – HSE Act framework
  3. Detailed consideration of PPE specifications
  4. Estimation of Risk
  5. Information, Training and Supervision in relation to PPE protection against an Influenza Pandemic.

Appendices

  1. Elimination and isolation
  2. HSE Act and Influenza Pandemic Preparedness
  3. Information, Training and Supervision

Glossary

Mask

Something worn over the nose and mouth and perhaps the whole face.

Surgical mask

A mask is worn to prevent the wearer coughing or sneezing infectious droplets onto others. Some surgical masks are additionally designed to protect the wearer from (a) droplets and (b) particulate matter in the air, and some are certified to P2 standard in this regard

Respirator

A device to protect the wearer from inhalation of harmful contaminants, classified by the amount of face coverage it provides and its method of protection, eg a half-face, negative-pressure, air-purifying respirator; or a full-face, pressure demand, supplied air respirator.

Viral status

Infectivity: Ability to infect a host – i.e. it only needs a few organisms to penetrate the host’s defence systems.

Tramsmissibility: Ability to spread from one host to another – if two people are close there is a high likelihood of infection

Virulence:Ability to replicate in the new host and cause it to shed viruses

Pathogenicity:Ability to cause disease in the host

SARS Avian influenza Common cold Influenza
Infectivity High (Subject to change) High High
Transmissibility Medium Low – Medium V High V High
Virulence Medium - V High Low Medium Variable
Pathogenicity V High High Low Variable

1 Occupational groups and settings to be considered

1 Workers managing situations where domestic bird flocks are infected by Avian Influenza:

  1. Veterinarians
  2. Bird Cullers
  3. Disposers of dead birds
  4. Shed disinfectors

The Department of Labour has been working with MAF over these issues and developed a draft Health Information bulletin on the matter early in 2005.

2 Workers responding in an Influenza Pandemic

These include workers in many different settings. Some of particular note are:

2 The structure of advice about PPE and its place in the wider picture – the need to consider the HSE Act framework

The use of Personal Protective Equipment is at the bottom of the hierarchy of protections specified in the Health and Safety in Employment Act. There are three levels of protection. They are:

  1. Eliminate (s8 of HSE Act)
  2. Isolate (s9)
  3. Minimise (s10)
    • 3a Engineering controls
    • 3b Work practices and administrative controls
    • 3c Personal protective equipment
      • 3c.1 Environmental Monitoring (s10(2)d)
      • 3c.2 Personal Health Monitoring (s10(2)e)

The HSE Act requires Employers to consider these three options in order of priority. In this scenario options for elimination are limited; the problem is ‘isolated’ in the sense that certain occupational groups will inevitably be more exposed than others and, therefore, option 3 ‘minimisation’ is also required.

Appendix B spells out some options for elimination and isolation, and this approach is elaborated in the companion document ‘Influenza Pandemic Planning – Analysis Tools’.

‘Minimisation’ has three levels of steps listed to reduce (but not eliminate) exposure. We have proposed a methodology below (Table 2) so that workplace participants can see the place of PPE in the overall prevention picture.

Concern exists about the third level of minimisation because the experience of many commentators is that PPE is generally expensive, is the least effective option and that good compliance is difficult or very difficult to achieve. The protection factors offered by respiratory protective equipment are often less than assumed, and may be much less if PPE users are not trained, if respirators are not fitted to individual’s faces properly and their use is not monitored properly.

Providing personal protective equipment (PPE) is a very visible and tangible step – whilst other steps to eliminate and isolate exposures, perhaps through changes in work organisation or procedures may be more difficult to discern. There is often a tendency to feel that once PPE has been provided no further control measures are required. Such notions can lead to dangerous complacency.

One way of extending the overall picture would be to estimate risks faced in different occupational settings and specify prevention measures based on the level of risk, as set out in Section 4 below.

Providing PPE is also more complex than just issuing equipment, particularly for Respiratory Protective Equipment (RPE). In New Zealand and Australia, the recommendations of AS/NZS 1715 and 1716 should be followed as a minimum[1].

This will require at least a management system for PPE including:

and other requirements.

3 Detailed consideration of PPE specifications

Routes of transmission

The possible methods of transmission of influenza are:

Aerosols Industrial experience is that where droplets are forcibly expelled there will be aerosolisation (and see below). The particle size, physical nature and other characteristics are important in the selection of the correct respiratory equipment provided. The physiological requirements related to respiratory equipment are important[2] as are the limitations of respiratory protective equipment[3] including ‘wear time’, face seal and other critical issues.

Droplets It is assumed to be the most important route ie from sneezing or coughing.

Contact There is clear evidence that this is an important route of transmission, for example from hand to mouth.

Information about droplet sizes in relation to pandemic influenza does not appear to be well developed.

Personal Protective Equipment (PPE) other than Respiratory Protective Equipment (RPE)

There is no argument that PPE will be required for workers exposed to the virus. This PPE will include splash protection, especially for the eyes, and protection from the inhalation of infected droplets or aerosols.

Splash protection can be obtained by the use of disposable overalls (reducing the chance of on-contamination during cleaning), face shields or goggles and respiratory protection.

Effectiveness of respirators (disposable masks)

There is uncertainty about the size ranges of the particles comprising infectious bio-aerosols, the number of particles that a person may be exposed to if not wearing a mask and the number of particles that must breach the host’s defences to initiate disease.

However, pure water droplets of diameters 100 and 50 microns falling in air with a relative humidity of 50% have been measured to evaporate completely in 1.3 and 0.3 seconds respectively[4].

Respiratory droplets containing dissolved and suspended substances would not evaporate completely and would do so less quickly.

However, it can be assumed that small water droplets containing respiratory secretions will desiccate rapidly and result in extremely fine particles in the size range of 0.5 to 12 microns. These are referred to as droplet nuclei and would waft on air currents rather than settle under the influence of gravity. The desiccation proceeds more rapidly as the droplet gets smaller.

Filtration of particles by typical filter media proceeds by five mechanisms:

As the size of the particles to be filtered changes, the relative contributions of these methods varies. As a consequence of the differing effectiveness of the 5 methods in relation to different particle sizes, there is a particle size at which filtration rates are lowest, and this is estimated to be 0.3 microns[5].

This means that:

Therefore, a prudent risk management approach indicates that workers in close contact with infected people, and where aerosolisation may ocurr, should use P2/N95 masks in preference to surgical masks.

Surgical masks do have value in health care settings to reduce droplet (but not aerosol) transmission from symptomatic patients (where the patient wears the surgical mask and the worker wears a P2 mask) or in exceptional cases for essential workers who cannot wear a P2 mask (for example due to COPD, asthma or similar respiratory conditions).

Overseas Reactions

As a result of arguments like these the American Federation of Labour and Congress of Industrial Organisations (AFL – CIO) wrote to the Director of the Centres for Disease Control (CDC) asking that Interim Guidance for Health Care workers Caring for Patients Potentially Exposed to Aerosolised Yersinia Pestis from a Bioterrorism Event, which advised that a surgical mask was sufficient protection for the healthcare workers exposed to plague patients, be withdrawn[7].

Evidence that the document was withdrawn appears at a website dated April 14, 2005[8] and on another website referring to that date[9].

More recently, the American Pandemic Flu Plan published by the Department of Health and Human Services, which advised the use of surgical masks by health care workers, attracted similar criticism from the AFL – CIO. On December 21, 2005, the AFL-CIO petitioned OSAG (at the U.S Department of Labour) to develop an emergency standard for pandemic Influenza preparedness, citing surgical masks as ‘Not being certified by NIOSH as respiratory protection’[10] or as consistent with advice about protection against Avian influenza issued by the CDC.

Monitoring and evaluation

Disposable respirators are only effective if a tight face seal can be obtained. This requires individual face-fitting tests and may involve the provision of a selection of masks in order to accommodate different face shapes and sizes as well as monitoring of their use.

An effective respiratory protection programme is complex, time consuming, and expensive. It is built upon the foundations of:

Continuous maintenance of protection is therefore difficult.

Other Respiratory protective Equipment

Several levels of Respiratory Protective Equipment offering greater levels of protection exist:

High risk

Medium risk

The practical limitations in terms of comfort, maintenance, reduced visibility and communication etc. mean that such equipment is unlikely to be appropriate for pandemic influenza, except in well defined circumstances where there is potential for high exposure for short periods.

Levels of protection reported in the literature.

Another way of expressing these conclusions is to say that different types of respiratory protection equipment give different levels of protection.

It is also clear that nobody can be quite sure what (numerical) level of protection be can be attached to each type of equipment.

One study that was conducted to answer this question in a particular setting concluded, in part, that[11]: the use of respiratory protection equipment reduced risks by the following proportions:

Surgical mask: 2.4 fold
Disposable dust, mist, fume or disposable high efficiency particular air filtering mask (HEPA): 17.5 fold
Elastomeric HEPA cartridge respirator 45.5 fold
Powered air purifying respirator (PAPR). 238 fold

This single study should be interpreted as providing indicative relative levels of personal protection only. It cannot be taken as providing accurate numerical information about the different levels of protection available from the different Respiratory Protective Devices. However, it appears to support the ideas that P2 respirators provide a significantly greater level of protection than surgical masks.

4 Estimation of Risk

Different workers in different settings and different workplace circumstances are exposed to different risks. These will include:

Virus status

Infectivity, transmissibility, virulence and pathogenicity (See Glossary)

Tasks

The inherent risks of a person’s task – the degree of exposure to infected droplets and aerosols (concentration x time)
Contact with other people
The wearer’s rate of work (and breathing rate)
Familiarity of the wearer with infection control principles
Training to avoid hand – face contacts (e.g. microbiologists)
Possibilities for isolation
Opportunities for hand washing and drying

Work management controls

Environmental controls
Administrative controls
Training and supervision of employees
Familiarity with principles of infection control
Monitoring of employees (exposure and health)

Training in a PPE Programme

Clear advice and information given
Extent to which generic advice is adapted to the particular workplace
Fitting (selection of a respirator that fits the face)
Fit testing (practise using it so ensure a good fit)
Use is practised beforehand
Compliance is monitored

One way of evaluating the risks faced by different groups of workers is shown in Table 1.

View Table 1

Table 2 presents a way in which the protection programme can be specified according to the level of risk faced.

View Table 2

5 Information, Training and Supervision in relation to PPE protection against an Influenza Pandemic.

Compliance with best practice regarding PPE usage is vital and employees will need to be given information and training in its use and be properly supervised and monitored.

The importance and potential effectiveness of training for PPE use is generally underestimated. Full details are spelled out in AS/NZS 1715 and 1716. These standards should be the basis of a complete training programme.

The use of PPE, apart from respiratory protection, such as overalls and eye protection, is relatively straightforward.However their use without prior education and training still places the wearer at risk of harm.

The safe use of respiratory protective devices requires a certain amount of dexterity and opportunity for practice. This means employees must be given the opportunity to try using PPE beforehand to discover what the best fit feels like, donning, fit checking and removal methods. Including education to ensure a level of understanding in their safe use.

It will be no good to hand out masks in the event of a pandemic and expect people to work out how to use them in a pressure situation.

This is important, given that the compliance with RPE usage was credited with preventing further infection of HCW nursing SARS patients in Toronto[12].

Appendix A – Examples of Elimination and Isolation:

Appendix B – Provisions of the HSE Act

In addition to the requirements under the Civil Defence Emergency Management Act 2002, planning should include obligations under the Health and Safety in Employment Act 1992.

Employers must take all practicable steps to mitigate the risk and protect employees, especially those at high risk from pandemic influenza. Employers need to actively plan to cover their risks and the risks to their workers and the public.

The most relevant sections of the Health and Safety in Employment Act 1992 are:

Section 6: “All practicable steps”

Every employer shall take all practicable steps to ensure the safety of employees while at work; and in particular shall take all practicable steps to:

Sections 7-10 describe a hierarchy of action for the management of hazards

Where a significant hazard, including the likelihood of avian influenza, is identified, the Act sets out the steps an employer must take:

  1. Where practicable, the significant hazard must be eliminated (section 8);
    • This may involve removing the hazard or hazardous work practice from the workplace.
  2. If elimination is not practicable, the significant hazard must be isolated (section 9);
    • This may involve isolating or separating the hazard or hazardous work practice from people not involved in the work or the general work areas. It could mean reducing the potential for contamination through changing work practices to achieve a greater degree of social distancing, or installing screens or barriers.
  3. If it is impracticable to eliminate or isolate the hazard completely, then the employer must minimise the likelihood that the hazard will harm employees (section 10). In addition, the employer must, where appropriate:
    • Provide, make available to, and ensure the use of suitable clothing and equipment to protect the employees from any harm arising from the hazard;
    • Monitor employees’ exposure to the hazard;
    • Seek the consent of employees to monitor their health; and
    • With their informed consent, monitor employees’ health.

This includes introducing work practices that reduce the risk. It could limit the amount of time a person is exposed to the potential hazard, or the use of protective clothing and/or equipment.

In some special situations, i.e. where work must continue for humane reasons or the maintenance of civil order, minimising the hazard may involve the use of prophylactic anti-viral medicines.

Refer to the Ministry of Health site for detailed guidance on appropriate personal protective equipment (PPE) for workplaces.

Sections 12 and 13: Information, Training and Supervision

Employees must be given information - in a form they are reasonably likely to understand – about:

Employees must be trained in the safe use of plant, objects, substances and protective clothing and equipment the employee is required to handle Although it is not stated in the Act, ‘adequately trained’ may be taken to mean:

  1. The employee knows how to do the job properly
  2. The employee knows the hazards of the job
  3. The employee knows the safe way to do the job

Supervision would be required until the employee can demonstrate these three things.

In the instance of pandemic influenza, the programme of training suggested in Appendix C would be one way of providing the required information.

Section 28A: Employees may refuse to perform work likely to cause serious harm

Employees have the right to refuse to perform work if they believe it is likely to lead to their suffering serious harm. However, their belief must be on reasonable grounds, and they must have attempted to resolve the matter with their employer before they can continue to refuse. The right to refuse unsafe work does not apply unless the understood risks of the work have materially increased. The right of an ambulance worker or nurse to refuse is therefore different to that of, say, a carpenter. It is also different to that of a sworn staff-member of the police, fire service or armed forces.

Ethical considerations of health staff, and the actual versus perceived risk to the individual would need to be considered.

The question in the case of infectious disease would amount to whether the exposure to the worker would exceed that which could be expected in the general community, and whether the efforts of the employer to eliminate, isolate and minimise harm would be sufficient to ensure worker safety.

NB: Independent contractors and volunteer workers have the right to withdraw their labour or services at any time, including when they feel the work environment presents an unsatisfactory level of risk.

Appendix C – Comments on Training in respirator use.

To get the most protection from wearing a respirator, it is a possible to think in terms of the 6 stages of information and training; selection, fitting, fit testing, fit checking; removal and disposal:

Stage When What the user needs to know and do
1 Limitations Analysis required beforehand
  • Is the effectiveness of the PPE adequate for the risk involved?
  • To see if a person or group of people are unlikely to be able to use the PPE - because the work-rate is too great or the need to wear goes on for too long
  • To see if medical assessments are required – because a person may not be able to wear PPE without compromising their health due an existing medical condition
  • To see if there is a realistic chance that the PPE can be worn and will be worn.
2 Information and training Well before the need for use
  • The place of PPE and respirators in the overall scheme of protection – the use of other PPE, the importance of hand washing
  • That respirators to not eliminate risks entirely and hence don’t have a false confidence and hence –
  • Use all protective strategies available
  • Do not engage in high risk activities unless wearing the right respirator for that level of risk
3 Selection of a well fitting respirator Well before the need for use
  • That face shapes and sizes differ from person to person
  • That different size respirators are available
  • That a badly fitting respirator is ineffective
  • Facial hair invalidates effective use of disposable masks
4 Fitting Well before the need for use
  • There are standard methods of putting on a respirator
  • There is a certain level of dexterity in this – so practice is needed
5 Fit testing Well before the need for use
  • That respirators can leak – but that proper selection, fitting, fit testing and adjustment can inform the use of respirator limitations and what a proper fit feels like – and therefore reduce this markedly
6 Fit checking Every time it is put on
  • How to perform a fit check
7 Removal and Disposal After use
  • Techniques for removing respirators and their methods of disposal

Footnotes

[1] The most up-to-date documents are AS/NZS 1715:2005 (Selection, Use and Maintenance of Respiratory Protective Devices-In final stages of review) and AS/NZS 1716:2003 (Respiratory protective devices).

[2] A great deal of work is being carried out by the working bodies of the ISO (International Standards Organisation) on this. Particularly important are the breathing volumes and rates required for different types of RPE.

[3] American Thoracic Society. (1996). American Protection Guidelines. Am. J. Crit. Care Med. Vol. 154. Pp 1153-1165.

[4] Aerobiology of infectious agents. Eugene C Cole. Proceedings of a Workshop (convened by Centre for Disease Control) on Respiratory Protection for Airborne Infectious Agents. Atlanta, Georgia. December, 2004.

[5] Aerobiology if infectious agents. Eugene C Cole. (See full citation above.)

[6] Protecting the faces of health workers. Yassi A and Bryce E. The Change Foundation and The Ontario Hospital Association. 2004. Occupational Health and Safety Agency for Healthcare in British Columbia. 2004

[7] Letter from Peg Seminario, Director, Department of Occupational Safety and Health, AFL-CIO to Julie Louise Geberding, Director, CDC. Letter dated 11 April 2005. [pdf file, external site]

[8] See: Occupational Safety & Health Reporter, Volume: 35 Number: 15, April 14, 2005

[9] See: http://www.unit47.org/news/041905.html

[10] See: http://www.afscme.org/press/pr060103.pdf

[11] Barnhart S, Sheppard L et. a.: Tuberculosis in health care settings and the estimated benefits of engineering controls and respiratory protection. JOEM. Vol. 39. No. 9 September 1997.

[12] Protecting the faces of health workers. Yassi A and Bryce E. The Change Foundation and The Ontario Hospital Association. 2004. Occupational Health and Safety Agency for Healthcare in British Columbia. 2004