CBRN is the abbreviation used to describe the malicious use of Chemical, Biological, Radiological & Nuclear weapons, primarily with the intention to cause serious harm or destruction.
The hazard posed by these materials varies:
Poisoning or injury caused by chemical substances, including traditional (military) chemical warfare agents, harmful industrial or household chemicals.
Illnesses caused by the deliberate release of dangerous bacteria or viruses or by biological toxins (e.g. ricin, found in castor oil beans).
Illness caused by exposure to harmful radioactive materials.
Life-threatening health effects caused by exposure to harmful radiation, thermal or blast effects arising from a nuclear detonation, or a small dirty bomb.
Can you protect against these serious threats? yes to some extent, a Hazmat Suit designed to cope with all the above, a Gas Mask with the correct CBRN Filters can limit some of the immediate threat, especially to chemical and biological agents in an urban setting, and of course CBRN gloves and over boots must correctly taped for total protection.
Terrorists have been trying to get there hands on a small dirty bomb ie explosives and nuclear material for decades, there has also been many attacks' with nerve agents around the world.
Keep a Gas Mask and hazmat suit handy in the car, they take up very little space but can be accessed quickly.