How important are those radiation warning signs that must be displayed on vehicles transporting radioactive material?
Let's look at what happens when a technician and his assistant traveling in the vehicle are unconscious after a traffic accident:
The traffic officer will see the signs warning the public that there are radioactive materials in the vehicle. The officer will then proceed to phone the emergency telephone number displayed on that sign. Let's say there is no answer. The officer has to assume that the source is "out of the container" and the possibility of exposure to ionizing radiation exists. Since the officer's job is to protect the public, he then will barricade the area around the vehicle containing the radioactive material and prevent anybody from going near the vehicle, including ambulance-responders.
Because the RPO did not answer his phone, there is danger that the technician and his assistant could bleed to death. For this reason the RPO is actually employed 24/7. The ideal procedure would be for the RPO to direct the traffic officer to locate the survey meter, to instruct the officer on the meter's operation to have the officer verify that there exists no danger of exposure then direct the officer to locate the source container.
A vehicle is involved in an accident and the occupants are unconscious, however, there are warning signs on the vehicle. For argument sake, let's assume that the driver neglected to remove the warning signs at the office and there is no radiation source in the vehicle. The Traffic officer will not be able to find the source container nor the survey meter, so what is the next logical step? The officer is trained in the procedure to barricade the vehicle "containing the radioactive material" and to prevent anybody form going near the vehicle. The officer will probably contact the Hazardous Material agents to help him find the source. They will fly in by helicopter. This scenario is even worse than the first scenario since no-one can assist the occupants of the vehicle until the source is found.
Who do you think is going to pay for this exercise?
The answer is to prevent these impasses by assuring that two names and two telephone numbers are displayed on the warning signs on the vehicle as per the requirements. In addition, the warning signs shall be removed from the vehicle when the radiation source is not in the vehicle to avoid the resulting delay that may occur.
Hennie De Wet
NDT Level III Practitioner