Radioactive Container Truck Spewing Gamma Rays Into Traffic on I-270 in Saint Louis, Missouri --- And this is legal ?

The U.S. government has regulations regarding the transportation of radioactive material. A summary of these regulations can be read in this document from the Nuclear Regulatory Commission. In particular, I found the following information relevant. Since the truck is labeled with a placard saying "Radioactive" and "7" for U.N. Class 7 hazardous material (radioactive material), the following rule applies:

A placard on a vehicle is only required if the vehicle is carrying a package bearing a Yellow 3 label or low specific activity material.

So the truck was carrying material labeled with a "Yellow 3" radioactive material label. Here's what "Yellow 3" means:

Label	Surface Radiation Level		Radiation Level at 1 Meter
Yellow 3	Exceeds 50 millirems/hour	OR	Exceeds 1 millirem/hour

However, there are maximum radiation levels for closed (container) transport:

Type of Transport	Maximum Radiation Limit
Common carrier non-exclusive use (closed)	200 millirems/hour on the surface of the package 10 millirems/hour at 1 meter from any surface of the package No limits specified outside the vehicle
Contract carrier exclusive use (closed)	1000 millirems/hour on the surface of the package 200 millirems/hour at the surface of the vehicle 10 millirems/hour at 2 meters from any surface of the vehicle 2 millirems/hour in the vehicle cab

Given that the truck was carrying "Yellow 3" material, either the surface dose rate exceeds 50 mrem/hr or the dose rate at 1 meter exceeds 1 mrem/hr. Assuming the tighter "non-exclusive" restrictions, the limit is 10 mrem/hr at 1 meter. Accounting for the material probably being centered along the midline of the truck, the measurement was made around 3 meters away. Given this, we would expect the dose rate to be in the range 0.1 to 1.1 mrem/hr. If the "exclusive" conditions are met, then the limit is 10 mrem/hr at 2 meters from the surface of the vehicle, which is about where the measurement was made. So their measurement of 0.3 mrem/hr (but probably more) is well within these limits as well. As a comparison, flying on an airplane gives a radiation dose at a rate of about 0.5 mrem/hr, which is about what that measurement was. Driving in the cab of a truck at the limit of 2 mrem/hr is only about 4 times the dose rate of flying in an airplane. Last, I have shipped radioactive material before, and I know that these regulations are strictly followed by shipping companies. Dose rates are measured with a Geiger counter at the surface of the container and any other locations specified, and shielding is increased when necessary. There are tons of legitimate uses for radioactive material, and the commerce is well-regulated. Mark [BRAWM Team Member]