What is the case for the nuclear emergency planning community’s snobbishness about improvised respiratory protection for the general public?

In my many years as an emergency planner in the nuclear industry I’ve never heard a real debate about respiratory protection as a public protective action in the event of an accidental atmospheric release of radioactivity. It has always been dismissed because without proper masks and fit testing the protection factors offered are compromised.

In 1981 the IAEA [1] identified that respiratory protection was one way to reduce dose uptake in workers and members of the public. It recognised that high levels of protection require properly designed and fitted devices and realised that these would only be available to those with planned roles in a response. They accepted that if any use is to be made of such measures by the public, the simple equipment and techniques to be employed can only be of a very rudimentary nature.

They provided a quite extensive table of filtration factors for common materials. This included the finding that 16 layers of man’s cotton handkerchiefs provides a geometric mean efficiency of 94.2% against aerosols of 1-5 μm particle size – a protection factor not to be sneezed at. At eight layers the efficiency drops to 88.9%. A single bath towel is worth 73.9%.

The public, they said, “can be advised to use such simple items while proceeding to take shelter, and possibly during sheltering. Similar precautions could be recommended while members of the public were being evacuated from a contaminated area”.

In 2002 the US NCR published a document [2] which suggested that improvised respiratory protection can be used as a secondary protective action that can be used to provide a nontrivial level of additional protection. They also provide a table of protection factors.

In 2007 IAEA stated that [3] “Improvised respiratory protection (e.g. a wet cloth over the mouth and nose) has been shown to be effective but it has not been demonstrated that the public will apply it effectively during an emergency. Improvised respiratory protection should not be assumed to provide adequate protection from an inhalation hazard and therefore its implementation should not be allowed to interfere with evacuation or sheltering”. This does not say that improvised respiratory protection should not be recommended under any circumstances; it just says it should not be used instead of shelter or evacuation.

The latest advice on the protection of the public in the event of a nuclear accident from PHE [4] makes no mention at all of RPE, improvised or otherwise. This publication suggests a dose reduction factor of 0.6 for inhalation dose from shelter in place over the period of a release.

So why have we taken improvised respiratory protection out of our tool box of techniques to reduce public dose? It seems to offer protection factors at least comparable with shelter in place for particulate activity.

We worry about golf courses and caravan parks within our DEPZs where shelter in place is considered likely to be ineffective. Could we at least provide a supply of half decent face masks with the stable iodine tablets we store at these establishments as a secondary protection while thinking about evacuation?

Does the Covid-19 experience that shows that large fractions of the population will wear face masks when advised and has made them far more available to the public change our current attitude?

 

  1. IAEA, Safety Series No. 55, Planning for Off-Site Response to Radiation Accidents in Nuclear Facilities
  2. US NCR, Perspectives on Reactor Safety, NUREG/CR-6042, Rev. 2 SAND 93-0971
  3. IAEA Safety Standards Series No. GS-G-2.1, Arrangements for Preparedness for a Nuclear or Radiological Emergency (2007), https://www-pub.iaea.org/MTCD/Publications/PDF/Pub1265web.pdf
  4. PHE, Public Health Protection in Radiation Emergencies, PHE-CRCE-049, (2019).

Learning for nuclear emergency planning from COVID-19?

The model of the UK response to a nuclear emergency that results, or may result, in a plume of radioactive material spreading across populated areas of the countryside is to get the local responders, notably the local authority, emergency services and health services, in one place to discuss, decide, coordinate and respond.

Within the model is a unit called the Science and Technical Advise Cell (STAC) with the mission “to ensure timely coordinated scientific and technical advice during the response to an emergency”. We were told that “The STAC should bring together technical experts from those agencies involved in the response and who may provide scientific and technical advice to the Gold Commander. The purpose of the cell would be to ensure that, as far as possible, scientific or technical debate was contained within the cell so that the SCG (and others involved in the response) received the best possible advice based on the available information in a timely, coordinated and understandable way.”

Implicit in this process is the assumption that in any event there is an objective truth and that if scientists chat about it for a while they will determine and understand that truth and be able to explain it to the decision makers who have been too busy on other aspects of the response to explore the science for themselves. The decision makers will be jolly grateful to the STAC and, armed with the scientific consensus, will go on to make the right decisions. They might even say time after time that they are being driven by the science.

In this ideal world, these decisions will be reported to the public and to the media, will be implemented and the crisis will be bought to a close. Also in this ideal world the decisions turn out to be the “right” decisions and the only decisions that could be considered to be “right”, all other options, explored and unexplored, being “wrong”.

One thing we have definitely seen with the coverage of Covid-19 is that the media will not just forward your advice to the public as you might hope. Instead they will turn out an army of interpreters who, fearful that Mrs Miggins and her neighbours will not understand that those in a defined area are being asked to shelter and those outside the area are not, will explain at length what they think “shelter” means and why it has been recommended. They will then find a talking head to explain it again and then another to say that the previous interpretation was wrong and that the public should be being advised to do something else entirely. They will summarise by saying that there is a lack of clarity in what the advice is and who it applies to before cutting to a member of the public who will confirm, in response to a loaded question, that they don’t understand the advice and that they are very worried.

Returning to the decision making, the major issue is that the science does not give all the answers. We may be able to estimate radiation doses to the public, with and without protective actions, but these will be educated guesses rather than accurate. The amount of dose saved (benefit) that makes a protective action (with a cost) worthwhile is debatable and probably different for different people in different situations. The decision to interrupt the lives of people and ask them to stay in their homes knocking back stable iodine tablets is therefore a judgement call not the outcome of a neat equation. This is particularly true when you realise that the estimates of future doses are horribly dependent on assumptions made about what is happening, and what is going to happen, in the bowels of a damaged nuclear facility, what the weather will be when the activity gets out and where the members of the public will be and what they will be doing. Again the media will bring out an army of “experts” to discuss the technology, the science and the decision making process and will argue that the science is debatable, the process flawed and that any of the decisions made are dubious.

Maybe what should happen is that advisors advise and decision makers decide. The spokesperson issuing the advice should state that the decisions have been taken by the Strategic Coordination Group who took into account scientific advice, advice about the incident and how it could develop and the concerns of and for the people affected.

The media should be asked to transmit the advice as given and to resist reheating and reinterpreting it.

That will work.

What are the lessons for the nuclear industry from Covid-19? How do we ensure that our protective action decision making process is robust, transparent, unambiguous and trusted to ensure a high level of public compliance and optimum dose reduction?