Hints for First Responders About Detecting Radiation
First responders of all disciplines may be the first people to need to be aware of the presence of radiation at an incident or during the conduct of their typical daily field duties.
Visual Clues
Responders can identify the potential presence of radiation by looking for visual clues such as the various signs, markings, labels and placards that are used in shipping, transport, and at fixed facilities that use and possess radiation sources or devices that produce radiation. More information on visual clues associated with radiation can be found in an International Atomic Energy Agency report, pages 38-39, and a U.S. Health and Human Services document.
The U.S. Department of Energy has developed a very useful radiation job aid that can be laminated and placed in all response vehicles. This aid has visual clues and also basic radiation-response guidance.
Radiation Detection Tools
As radiation cannot be detected by any of the human senses, it would be very appropriate for first responders to use a radiation detection or measurement tool to identify the presence of radiation above the normal background levels that exist in their community.
Because there are multiple first-responder disciplines, it should come as no surprise that each responder group may have a different mission. These mission differences can place some individuals closer to a radiological impacted area and therefore pose a greater potential of receiving higher radiation doses and the potential of working in higher dose-rate fields.
The mission of law enforcement is typically in the realm of interdiction. Active radiation monitoring while on routine patrol or during a response to an incident will warn responders of the presence of radiation. Once warned of the presence, the responder can then take appropriate actions to address the safety of the response personnel, to isolate the area, and to notify additional responder assets.
It must be mentioned that although radiation may be detected by these devices and the detection must be investigated, there are circumstances where the increase in radiation levels may be due to the presence of naturally occurring radioactive materials in building materials, legal uses of radiation sources in industry and medical settings, or from patients who have undergone a medical treatment using sources of radiation as opposed to nefarious activities.
At any response location where radiation has been identified, the radiation authority for your jurisdiction should be notified. The Conference of Radiation Control Program Directors has a map showing state radiation authorities in the United States. Radiation authorities may also be able to give you specific state guidance for radiation response and provide radiation-response personnel and equipment. It is always best to involve them in your development of a plan for a response to a radiation incident as opposed to waiting until you are actively involved in an incident.
Helpful Documents
There are documents that can be used during the development of your plans for a response to an incident involving radiation. These documents can also help you create response guidance for your agency. These include the National Council on Radiation Protection and Measurements (NCRP) Report No. 138, Management of Terrorism Events Involving Radioactive Material (2001), NCRP Report No. 165, Responding to a Radiological or Nuclear Terrorism Incident: A Guide for Decision Makers (2010), and NCRP Commentary No. 19, Key Elements of Preparing Emergency Responders for Nuclear and Radiological Terrorism (2005). These are available for purchase through the NCRP website. Others include the International Atomic Energy Agency (IAEA) Manual for First Responders to a Radiological Emergency (2006), which is free through the IAEA website and the American Society for Testing and Materials (ASTM), Standard Practice for Radiological Emergency Response, E2601–08, which is available for purchase at the ASTM website.
The ASTM radiation response standard is also available through the Responder Knowledge Base (RKB) website. You can subscribe to the RKB free. Once you have an account on the RKB, log in and go to the RKB Recommends section on the home page. In that section, you will find a link that allows access to ASTM Committee E54 standards. The U.S. Department of Homeland Security makes the ASTM Committee E54 standards available to federal government and responder users of the RKB. The ASTM standard can also be found at the ASTM store.
Your jurisdiction should develop guidance for radiological response based on the local jurisdiction. The guidance your jurisdiction develops should be used as a starting point for radiological response and be adjusted based on the incident type and phase of the incident. In longer operations, radiation dose management will be implemented to keep doses as low as reasonably achievable.
Guidance Tables
Below is an example of a radiation dose and dose-rate table along with the action taken when accumulated dose or dose rate is measured. Most electronic dosimeters sold these days will allow the user to program into the devices' preset alarm points.
Table 1 was developed using a number of the documents listed above.
Table 2 is an example of a generic stay-time table. The table is based on selected dose rates and the amount of exposure that any one responder is limited to receiving while in the field of radiation. Incident stay-time tables should be developed based on the radiological conditions that exist at an incident. A generic job aid is always good to have as quick reference for an initial response starting point.
| Alarm Set Point Type | Reading3 | Comments1, 2 | Responder Actions |
|---|---|---|---|
| 1st Dose Rate | 2 mrem h-1 | This is a generally accepted value to be used to establish the hot zone (exclusion area) for a response to a transportation accident involving radiation. | Continue rescue and investigation activities.
Establish exclusion zone. |
| 2nd Dose Rate | 10,000 mrem h-1
(10 rem h-1)
|
Recommended value listed in National Council on Radiation Protection and Measurements Report Number 138. | Leave the area unless rescue of known victims can be accomplished efficiently and within guidance values for accumulated dose alarms to responders.
Accumulated doses greater than 10 rem must be carefully considered. Seek expert advice. |
| 1st Accumulated Dose | 2,500 mrem
(2.5 rem) |
This is one-half of the 5,000 mrem annual regulatory exposure limit for occupationally exposed radiation workers. | |
| 2nd Accumulated Dose | 10,000 mrem
(10 rem) |
This is less than one-half of the 25,000 mrem dose value listed in EPA 400-R-92-001 for lifesaving or protection of large populations. Recommended value listed in National Council on Radiation Protection and Measurements Report Number 138. |
2. Basis of the value used is taken from the document indicated.
3. At the listed values, no immediate health effects from the radiation exposure would be observed in the responder.
| Dose Rate | Accumulated Dose Target | Down-Range Time |
|---|---|---|
| 10,000 mrem h-1 (10 rem h-1) | 25,000 mrem (25 rem) | 150 minutes (2.5 hours) |
| 10,000 mrem h-1 (10 rem h-1) | 10,000 mrem (10 rem) | 60 minutes (1 hour) |
| 10,000 mrem h-1 (10 rem h-1) | 5,000 mrem (5 rem) | 30 minutes |
| 10,000 mrem h-1 (10 rem h-1) | 2,500 mrem (2.5 rem) | 15 minutes |
| 10,000 mrem h-1 (10 rem h-1) | 1,000 mrem (1 rem) | 6 minutes |
| Dose Rate | Accumulated Dose Target | Down-Range Time |
| 2,500 mrem h-1 (2.5 rem h-1) | 25,000 mrem (25 rem) | 600 minutes (10 hours) |
| 2,500 mrem h-1 (2.5 rem h-1) | 10,000 mrem (10 rem) | 240 minutes (4 hours) |
| 2,500 mrem h-1 (2.5 rem h-1) | 5,000 mrem (5 rem) | 120 minutes (2 hours) |
| 2,500 mrem h-1 (2.5 rem h-1) | 2,500 mrem (2.5 rem) | 60 minutes (1 hour) |
| 2,500 mrem h-1 (2.5 rem h-1) | 1,000 mrem (1 rem) | 24 minutes |
| Dose Rate | Accumulated Dose Target | Down-Range Time |
| 1,000 mrem h-1 (1 rem h-1) | 25,000 mrem (25 rem) | 1,500 minutes (25 hours) |
| 1,000 mrem h-1 (1 rem h-1) | 10,000 mrem (10 rem) | 600 minutes (10 hours) |
| 1,000 mrem h-1 (1 rem h-1) | 5,000 mrem (5 rem) | 300 minutes (5 hours) |
| 1,000 mrem h-1 (1 rem h-1) | 2,500 mrem (2.5 rem) | 150 minutes (2.5 hours) |
| 1,000 mrem h-1 (1 rem h-1) | 1,000 mrem (1 rem) | 60 minutes (1 hour) |
| Dose Rate | Accumulated Dose Target | Down-Range Time |
| 200 mrem h-1 | 25,000 mrem (25 rem) | 7,500 minutes (125 hours) |
| 200 mrem h-1 | 10,000 mrem (10 rem) | 3,000 minutes (50 hours) |
| 200 mrem h-1 | 5,000 mrem (5 rem) | 1,500 minutes (25 hours) |
| 200 mrem h-1 | 2,500 mrem (2.5 rem) | 750 minutes (12.5 hours) |
| 200 mrem h-1 | 1,000 mrem (1 rem) | 300 minutes (5 hours) |
| Dose Rate | Accumulated Dose Target | Down-Range Time |
| 2 mrem h-1 | 25,000 mrem (25 rem) | 750,000 minutes (1.4 years) |
| 2 mrem h-1 | 10,000 mrem (10 rem) | 300,000 minutes (208 days) |
| 2 mrem h-1 | 5,000 mrem (5 rem) | 150,000 minutes (104 days) |
| 2 mrem h-1 | 2,500 mrem (2.5 rem) | 75,000 minutes (53 days) |
| 2 mrem h-1 | 1,000 mrem (1 rem) | 30,000 minutes (21 days) |
The following operational conditions have to be taken into consideration when considering the down-range time that an entry team can spend in the exclusion zone.
- Time to get from the entry location to the work location.
- The amount of time that has been projected to complete a mission.
- The time it takes for the entry team to leave the work area and arrive back at the exclusion zone/decontamination corridor.
- The amount of time needed to be surveyed and/or decontaminated.
There are various free training programs that are available to response organizations. The following are two different training programs that are delivered at your location that are free of charge:
- The U.S. Department of Energy Transportation Emergency Preparedness Program MERRTT course
- Counter Terrorism Operations Support (CTOS) – Center for Radiological/Nuclear Training
The three radiation job aids that should prove useful to your personnel are:
- U.S. Department of Energy radiation job aid that can be laminated and placed in all response vehicles. The radiation job aid has visual clues and basic response guidance.
- Electronic Dosimeter Alarm Point Guidance (Table 1)
- Down-Range Stay-Time (Table 2)