Re: Treatment of Contaminated Personnel

["J. J. Rozental" <josrozen@netmedia.net.il>]

At 05:56 PM 2/26/99 -0600, you wrote:
>>Let's consider the following:
>>Approximately 10 P.M. Friday,  a light truck with adequate placard was
>>transporting two gamma radiography containers: One housing a 3.7 TBq (100
>>Curies) Ir-192 source and the other a 0.74 TBq (20 Ci) Co-60 source. Close
>>to a small city, 20 km away, in a rural area, the truck was involved in a
>>road accident. The  truck collided with a vehicle, traveling in opposite
>>direction and overturned. The truck's driver, was seriously injured  and
>>unconscious and the radiographer's right leg fractured. Also 2 passengers
>>and one children from the other vehicle were injured, and could not be moved
>>fom the car. Considering that the radiographer could not move,   he asked to
>>the first person who came to help them for the survey meter. Following, he
>>confirmed a dose rate of  25 R/h next the vehicles and he concluded that one
>>or both sources could be unshielded...
>
>In response to this scenario, the Los Alamos training says: your stay time
>is 48 minutes so do your job as normal. If the dose rate exceeds 200 R/h,
>do a rapid extrication of the victims, as if there were immediate hazards
>such as vehicles about to explode. If the dose rate is >1000 R/h, back off
>and do not perform a rescue.
>
>I would value your comments. Thanks, mike
>"Shlala gashle" (Zulu greeting, meaning "Stay safe")
>mike (mcnaught@LANL.GOV)
>************************************************************************

Dear Mike, thank you for your information. With pleasure my comments:

a) In response to this scenario, the Los Alamos training says: your stay time
is 48 minutes so do your job as normal. If the dose rate exceeds 200 R/h,
do a rapid extrication of the victims, as if there were immediate hazards
such as vehicles about to explode. If the dose rate is >1000 R/h, back off
and do not perform a rescue.

Your statement was made considering the first step of the scenario, in
which, nevertheless  the radiographer could not move, he could use the
detector and measure the  dose rate of  25 R/h.

As the radiographer was not unconscious, no doubt he  instructed the first
responder on scene, fire brigade, police or medical team, how to survey at
different distances, starting  from his first  measure. The radiographer in
this first part, could manage the situation  as a Radiological Assessor,
providing to the response teams the best alternatives for rescue injured
people and control the situation. 

b) With reference to your values, I would like to inform that I do not
follow American guidance, but rather international recommendations, in my
activities for developing countries. For this case I consider  the ICRP 60,
1990 Ed. to limit the occupational exposure in emergencies, according with
6.3.2  (225)  and (S50) pages 52 and 76: The exposures in the control of the
accident and in the immediate and urgent remedial work should not to give
doses of more than about 0.5 Sv except for life-saving actions, which can
rarely be limited  by dosimetric assessments. The equivalent dose to skin
should not be   allowed to exceed 5 Sv, again except for life saving.
The IAEA BSS - Safety Series 115, 1996,  V.27 states: "All reasonable
efforts shall be made to keep doses to workers below twice the maximum
single year dose limit, except for life savings actions, in which every
effort shall be made to keep doses below ten times the maximum single year
dose limit, in order to avoid deterministic health effects on health".
In any single year effective dose is 50 mSv (II-5 b), page 91. So the total
of 500 mSv can be exceeded if justified for  life saving actions 
The ICRP emphasizes that ionizing radiation needs to be treated with care
rather than fear and its risks should be kept in perspective with other risks.
The IAEA V.28 emphasizes that workers who undertake actions  in which  the
dose exceeds the maximum single year dose limit shall be volunteers and
shall be clearly and comprehensively informed in advance  of the associated
health risk, and shall, to the extent  feasible, be trained in the actions
that may require.

d) Other comment on your remark: 

When you mention: "In response to this scenario, the Los Alamos training
says: your stay time is 48 minutes so do your job as normal." This proves
the importance of adequate training to first responders. Take into account,
for instance the accident scenario: Accident occurred in a rural region,
late in the night (10 PM).   If the remark is made to persons usually
working with radioactive material and  knowing the Radiation Protection and
Emergency Fundamentals is one situation,  if the remark is made to other
groups, eventually engaged and trained,  as first responder, the situation
is different if Radiological support group is not present. Well, this can
give rise to a long discussion...

d) Now let's take into account  the following  remark: If the dose rate is
>1000 R/h, back off and do not perform a rescue.
This value is a dose rate and should consider the time necessary for the
rescue. In case of the ICRP and IAEA recommendations, if the total effective
dose considered for life saving is 500 mSv (50 R), and  considering  a
scenario that the dose rate is 1000 R/h,  this means that the time for
rescue should be not more than  3 minutes. It is really a very high balance
for decision making.  
Just as reminder, this was one of many other situation that happen with me
in Goiania, not to life saving but to shielding the remnant source of Cesium
137 in the Radiological Accident of Goiania. In the first day that I arrived
in Goiania to coordinate the emergency response, I noticed that the
radiation  levels in the nearest sidewalk  at the Health Department  reached
values up to 3 R/h and the neighborhood was quite apprehensive. To reduce
the number of evacuated house and also recognizing the depressive state of
the local residents, I decided to shield the source next day.  The dose
rates measured at the surface of the remnant source were greater than 1000
R/h and equal to 40 R/h at distance of  1 meter. I trained during two hours
a select and  experienced group of the Secretaries of Health and the
Transport Department of the State of Goias and successfully we conduct the
operation and in this step the dose was reduced to values less than  1 R/h.

The complete above description is part of the Annex in my paper "Aspects of
the Initial and Recovery phases of the Radiological Accident in Goiania,
Brazil",  Proceedings of the International Symposium on Recovery Operations
in the Event of a Nuclear Accident or Radiological Emergency - IAEA, Vienna,
6-10 November 1989. If you which a copy please give me your  complete
address and I will send to you.



Best Regards, 

J. J. Rozental
<josrozen@netmedia.net.il>



jjrozental

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