Policy responses and statements

Name of organisation:

Health Protection Agency

Name of policy document:

Revision of HPA advice on Emergency Reference Levels for stable iodine prophylaxis following an accidental release

Deadline for response:

30 June 2006

Background: The Health Protection Agency (HPA) advises Government and other responsible bodies on the principles underpinning the response to radiological emergencies and specifies Emergency Reference Levels of dose (ERLs). The Agency has a responsibility to keep such advice under review. Thus, following a review by an expert panel of the risks posed by radioiodine and the prophylactic use of non-radioactive (stable) iodine, the Agency is reconsidering its advice on the protection of the public from accidental releases of radioiodine.

This document discusses the merits and demerits of six options for revising its advice. Options A, B and C relate to advice associated with the lower Emergency Reference Level (ERL) and options D, E and F relate to advice associated with the upper ERL. The Agency seeks comments on the appropriateness and extent of the arguments presented for each option considered and whether additional options or arguments are required to capture particular aspects of the decisions under consultation.

COMMENTS ON
HEALTH PROTECTION AGENCY
REVISION OF HPA ADVICE ON EMERGENCY REFERENCE LEVELS FOR STABLE IODINE PROPHYLAXIS FOLLOWING AN ACCIDENTAL RELEASE

The Royal College of Physicians of Edinburgh is pleased to respond to the Health Protection Agency on its consultation on the Revision of HPA advice on Emergency Reference Levels for stable iodine prophylaxis following an accidental release.

The document takes a rather negative view of possible contamination with I-131.  Although I-131 is a product of the fission of Uranium based isotopes to get large releases of I-131 would need some special factors.  If it is released by effluent into a water supply, it would only pose a risk if drunk.  There should be time to notify the relevant authorities and ensure no water is drawn form that source for the 4-6 weeks it would take for the I-131 to decay.  Also, in water it would disperse rapidly, significantly reducing the risk to an individual.

The most likely method by which a substantial amount of I-131 could be released would be sustained destruction of a nuclear power plant such as the fire at Chernobyl in a power station without a containment vessel.  This would allow I-131 to be released into the atmosphere and then be dispersed by wind.  It is unlikely that either a nuclear or radiological bomb would produce very much activity and this would be quickly dispersed (unlike some longer activity isotopes which could cause a greater threat to health over the long term).  Ingestion is really needed for irradiation so advice not to use unwrapped food products and cleaning food in running water should remove any I-131 falling on to food products within the house (in Ukraine, the main contaminant was home grown vegetables that the residents were told not to stop eating until 7 days after the fire).  There will need to be restrictions of agricultural products from any affected area.  It is this physical separation of the patient from the I-131 that will provide most protection.  Therefore, rapid dissemination of correct advice will be paramount in preventing disease.

The possible number of geographical sites which could be affected are limited, and it would therefore be sensible to concentrate efforts to these areas (eg close to nuclear power stations and plants such as Windscale).

Even allowing for this, the principle of “as low a dose as reasonably achievable” should be approved.  Therefore, those options in which the public are sheltered and given treatment if thyroid doses are expected to be >10mGy are preferable.  Even if shelter only reduces exposure by 50%, that is desirable, and will also protect from other radioisotopes in which iodine prophylaxis is unhelpful.

For these reasons, options C and E would be the best.

However, we do feel that the distribution of stable iodine tablets to the public at large or even to ‘at risk groups is very sensible.  Not only could this produce significant levels of public anxiety, one would suspect little used tablets are easily displaced.  Also, trying to keep these in date would be an issue and very expensive.

Although stocks could be kept at pharmacies or doctors’ surgeries, we fail to understand why stocks cannot be kept and dispersed by those with civil defence responsibilities (normally the fire brigade).

In conclusion, to answer these specific questions in the document:

Q1.  Do you think that the options presented adequately represent the range of alternatives available for revising ERL advice associated with iodine prophylaxis?

Yes.

Q2.  Do you think that all options have both potential benefits and drawbacks (ie pros and cons)?

Yes.

Q3.  Do you think that the pros and cons discussed cover the relevant issues?

Yes.

Q4.  Do you have additional views or information, relevant to one or more options, which you think should be included in the discussion?
No.

Q5.  Do you agree that options A and E are the most appropriate in the present circumstances? (Please give your reasons)

No.  Options C and E would be best for the reasons stated above.

Q6.  Are there additional issues that you think it would be appropriate for the formal advice stemming from this consultation to cover?

No.

Generally, this is a useful document but must be seen in the context of likely risk in the UK and also taking into account those agencies with a responsibility in this area which are already established.

Copies of this response are available from:

Lesley Lockhart,
Royal College of Physicians of Edinburgh,
9 Queen Street,
Edinburgh,
EH2 1JQ.

Tel: 0131 225 7324    ext 608
Fax: 0131 220 3939

[27 June 2006]