Procedures

Emergency Response Plan for Radioactive Spills - Procedures

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1. Purpose and Objectives

This document provides workers with the control procedures for cleaning up liquid radioactive spillages for gamma ray and beta emitting isotopes.

2. Definitions, Terms, Acronyms

Activity (A) Is the expected value of the number of nuclear transformations occurring in a given quantity of material per unit time. The SI unit of activity is per second (s-1) and its special name is the Becquerel (Bq).

Becquerel (Bq) is the special name for the SI unit of activity

Curie (Ci) is the old unit of activity 1 Ci≈3.7 x 1010 Bq

RSO - Radiation Safety Officer

RSPP - Radiation Safety Protection Plan

UQ RPA - University of Queensland Radiation Protection Advisor

3. Procedures Scope/Coverage

This procedure covers liquid spills only. This procedure should also be read in conjunction with Australian Standard AS 2243.4:1998 Safety in laboratories Part 4: Ionizing radiations where Appendix C6 and Table C4 contains guidance on the derived limits for surface contamination.

The local Radiation Safety and Protection Plan (RSPP) will also contain specific procedures for spill cleanup, notification and investigation and must be consulted prior to beginning spill cleanup procedures.

4. Procedures Statement

These procedures are intended to provide guidance in minimising the impact of accidents involving spillage of radionuclides in liquid form.

This document considers the response to a contamination incident in four phases:

  1. notification of RSO and other laboratory workers
  2. monitoring and control of the contamination
  3. decontamination of personnel, work areas and equipment
  4. incident investigation and reporting on the incident management database.

Accidents involving radiochemical spills can also involve skin penetrating and other injuries. Treatment of those injuries should as a general rule take priority over decontamination and should be dealt with in accordance with established first aid and medical procedures.

Monitoring should be performed at an early stage following an accident but not at the expense of delaying treatment. In general, attempts to remove radioactive contamination should only be commenced after the patient's condition has been stabilised and when the procedures can be performed without compromising medical treatment.

Generally unsealed radionuclides used in University labs are mostly of low radiotoxicity and only relatively small amounts are used. The immediate risks to health from contamination by such radionuclides would be minor in comparison to those from a life threatening injury. Even where the long term risks of cancer induction are considered, the risk of delaying treatment would still be far greater.

5. Sequence of Emergency Procedures

5.1 Step 1: Notify the RSO and other persons working in the laboratory of the occurrence of a spill

The organisational area RSO needs to assess the incident to determine the response required. If you are unsure of who the local RSO is, you will find their name in the Contact List shown as an attachment in the RSPP. Local area RSO contact details are also listed on the UQ Safety Contacts webpage.

A copy of the RSPP should be displayed in the lab and may contain specific procedures for cleanup as well as other information about notification procedures. You can access Safety Data Sheets (SDS) for the relevant radionuclides from PPL 2.80.04 Radiation Safety Data Sheets and these must be consulted when establishing a spill control plan, and to fully inform all personnel involved of the characteristics of the spilled material.

Where persons have been injured, the University emergency procedures should be activated by calling Security on 3365 3333. Minor spill incidents may be cleaned up by the user concerned if the RSO is unavailable, and the RSO notified of the incident as soon as practicable. For all contamination incidents, access to the area needs to be controlled by the RSO, or someone designated by the RSO for this task.

For incidents involving contamination of persons the RSO should ask all non‑essential personnel to leave the laboratory. Where a person has been contaminated, remove contaminated clothing and proceed to decontaminate any affected areas of skin as described in the decontamination of workers in Step 3 below. The RSO should designate another person to contain the spill as described in Step 2 so that it can be cleaned up when the more urgent task of personnel decontamination is completed.

Where there is need for a lengthy decontamination operation, a control point should be established just outside the laboratory where personnel can be checked for radioactive contamination as they leave the area.

5.2 Step 2: Contain the spill and monitor for contamination

Spill containment and cleanup procedures stipulated in the local RSPP must be followed.

All appropriate PPE (double gloves of a material protective to the material spilled, eye protection, overshoes, lab coat) must be donned before an attempt to clean up the spill is made.  

Absorbent paper or absorbent pads should be dropped onto the spill and the remaining material wiped up. Wiping should be inward, i.e. towards the centre of the spill so as to prevent the spread of contamination. The use of vermiculite as an absorbent is not recommended as it may create a dust inhalation hazard.

After the spill has been contained and mopped up with absorbent material, the extent of any remaining contamination needs to be determined. A careful survey should be performed using a meter with an appropriate response to the radiation emitted by the contaminant.

From the knowledge of the type of radiation emitted, the half-life and chemical properties of the contaminant, the RSO can determine the best course of action to allow the area to be released from further control. This will mean either immediate decontamination of the affected area, or closure of the whole laboratory to allow the activity to decay to acceptable levels (short-lived radionuclides only). The latter option is the more desirable option in terms of limiting occupational exposure and the production of radioactive waste. Unfortunately, this will rarely be practical because of operational constraints.

5.3 Step 3: Decontamination

5.3.1 General advice on decontamination

Decontamination should be carried out in a planned and logical manner by the RSO or a person experienced in radiation protection procedures designated by the RSO. Laboratories in which radioactive materials are used should maintain a decontamination kit so that the necessary materials are always at hand.

The following materials will be required for decontamination operations:

  • Radiation survey meter with appropriate response to the radiation emitted by the contaminant.
  • Appropriate protective clothing and equipment, such as lab coat, gloves and overshoes.
  • Suitable tongs or forceps to hold swabs while minimising dose to the hands.
  • Decontamination materials such as water, detergent, Decon90, Radiacwash, or other agents capable of removing or complexing with the spilled material. Hydrogen peroxide solution, potassium permanganate and sodium metabisulphite will be required where personal decontamination is necessary. Where radioiodines are used, a solution of 0.1 M sodium iodide, 0.1 M sodium hydroxide and 0.1 M sodium thiosulfate should be kept on hand for use as a decontaminant. Absorbent cloth or tissues should also be available.
  • Waste disposal containers lined with a non-absorbent material to prevent leakage should be used to contain contaminated material collected during the cleanup e.g. resealable plastic drum lined with a plastic bag. Where necessary, the outer container may also need to be lined with shielding materal such as lead sheeting.
  • Cleaning must continue until all removable contaminants have been removed. Surface contamination levels must be reduced below the Derived Working Levels for Surface Contamination levels specified in the Australian Standard AS 2243.4: 1998 Safety in laboratories Part 4: Ionizing radiations and summarized in Table 1 below. For details on the toxicity groups see Table A1 in the Standard. The majority of isotopes (e.g. 3H, 14C, 32P, 33P, 125I, & 35S ) used in UQ unsealed laboratories fall into Radiotoxicity Group 3 and 4.

Table 1 - Derived Workings Surface Contamination (Non-fixed)

Radiotoxicity Group

Maximum level within laboratory (Bq cm-2)

Maximum level within on skin or items leaving laboratory. (Bq cm-2)

Group 1

0.1

0.01

Group 2

1

0.1

Group 3a

10

1

Group 3b

100

10

Group 4

1000

100

5.3.2 Decontamination of workers

A general rule when attempting personal decontamination is to try the most gentle methods first. On no account should the skin be broken or treatment continued to the point where skin becomes inflamed or irritated.

5.3.3 Decontamination sequence

Carefully monitor body surface and clothing to localise contaminated areas. Remove clothing carefully to avoid spreading contamination. Store contaminated clothing in a labelled plastic bag or container.

Check for minor wounds or abrasions. These should be covered with waterproof adhesive coverings to prevent activity entering the body. If wounds are contaminated, they should be washed under running water (or sterile saline if available) and reasonable bleeding encouraged for about a minute. A sterile dressing should then be applied.

Remove contamination from around the nose, mouth and other body openings as a first priority. The mouth can be washed with dilute hydrogen peroxide solution and the eyes with tap water or 1% saline. Skin is best treated initially with mild soap and water; if this fails to remove contamination, Radiacwash towelettes can be used ‑ provided the affected area is not near the eyes.

Where the contaminant is 32P, a dilute solution of acetic acid (or common vinegar) has been found to be effective in removal.

For more persistent skin contamination, a saturated potassium permanganate solution is applied until the skin is deeply coloured, then washed off and allowed to dry. The area is then treated with a 10% sodium metabisulphite solution to remove coloration.

5.3.4 Decontamination of work areas and equipment

To prevent the production of respirable dust, only wet decontamination methods should be used. The removal of contamination should be done with the minimum of rubbing and the swabs should be frequently discarded as radioactive waste. Frequent monitoring needs to be performed to assess progress. The Radiacwash swabs used for skin decontamination have also been found to be of use in decontaminating metals and plastics.

Where contamination appears fixed after initial tests with simple wet wipes, further washing with a complexing agent such as Decon 90, Count‑off or Radiacwash will be required. The decontaminating solution should be left on the contaminated surface as long as possible to allow the chemical reaction at the surface to assist the decontamination. If decontamination is unsuccessful, treatment with an abrasive material may be required. This should only be done under wet conditions.

In some cases it may be better to remove an item of equipment or section of bench for storage, either permanently as contaminated waste, or temporarily until the contaminant has decayed sufficiently. In exceptional cases it might be necessary to seal in the contamination with concrete or paint. The advice of the Occupational Health and Safety Division must be obtained before sealing in any radioactive contamination or for approval to consign a contaminated item to the school or centre decay store

5.4 Step 4: Accident investigation and reporting

When decontamination is complete the RSO must investigate the accident and determine whether there are any deficiencies in procedures or if personnel need additional training. The RSO should prepare an incident/accident report on the OHS incident database. The local RSPP should be reviewed after any incident to identify any areas for improvement, and corrections/updates made as required to prevent a recurrence. The UQ RPA must be listed as a specialist advisor on any incident report that involves radioactive contamination.

This report must contain the following:

  • a description of the incident
  • extent of contamination of work area and workers
  • an estimates of any radiation doses to workers
  • decontamination operations performed and
  • actions proposed to be taken to prevent a recurrence.

In some circumstances it may be necessary to make a report to the statutory authority; this will be coordinated by the UQ RPA and the Occupational Health and Safety Division.

Custodians
Director, Occupational Health and Safety
Mr Jim Carmichael
Custodians
Director, Occupational Health and Safety
Mr Jim Carmichael