Why Radiological Threats are Attractive to Terrorists


The radiological threat is real and growing according to the April Time Magazine article titled “Inside the Uranium Underworld: Dark Secrets, Dirty Bombs.

“It would change our world,” President Obama said of a potential dirty bomb in April 2016. “We cannot be complacent.”


“In a sense we’ve been lucky so far, I honestly think it is only a matter of time before we see one of these dirty-bomb attacks.”

–Sharon Squassoni, Director of the Proliferation Prevention Program at the Center for Strategic and International Studies (CSIS) – TIME INC.

Last fall, an undercover investigative group demonstrated how simple it was to obtain radiological materials for a dirty bomb – right here in the United States.

This spring, in response to the growing radiological threat, ambulances in our Nation’s Capital were fitted with radiological detection equipment. Larger devices of this sort have been put into operation at our nation’s ports just this past year. The goal here being early detection before the harmful radioactivity can be put to use in any act of terror – whether at a crowded event, on a city block or in the mail of a targeted organization.

What is a Radiological Mail Threat?

The Department of Homeland Security defines a radiological attack as “the spreading of radioactive material with the intent to do harm.” This can include an explosion of some kind and the resulting unprotected exposure to radioactive material. According to the United States Postal Inspection Service, radiological dispersion can be achieved “by combining a radiation source with a conventional explosive to create a ‘dirty bomb’ that can be introduced into the mail stream as a package.”

Why are Radiological Threats be Appealing to Terrorists?

Terrorist use of a Radiological Dispersion Device (RDD) — or “dirty bomb” — is considered far more likely than use of a nuclear explosive device. This appeals to terrorists because the RDDs require less technical knowledge to build and deploy compared to a nuclear device. Furthermore, the radioactive materials in RDDs are widely used in agriculture, medicine, industry and research, and are easier to obtain than weapons grade uranium or plutonium.

What is Different About This Threat?

By itself, radiation is odorless and invisible, and there are few clues about the danger. However, in some ways, the threat is very much like a bomb (or explosive) threat due to the fact that in order to disperse the radiation, a conventional explosive device (or Radiological Dispersion Device RDD) is needed. The difference lies in the fact that there is radioactive material being scattered. And therefore, additional detection methods apply here.

Radiological threats by explosion may affect:

  • Small, localized areas (e.g., a street, a mail room, a single building, or city block)
  • Large areas, up to a few square miles, depending on the nature of the dispersion and the amount and type of radioactive material

What are the Types of Radiological Threats?

  1. Radioactive sources can be solid, aerosol, gas, or liquid.
  2. Radiological Dispersal Devices (RDDs) or ‘Dirty Bombs’ explosion produces radioactive and nonradioactive shrapnel and radioactive dust over a targeted area.

Explosion causes:

  • Radiation contamination, commonly
  • Radiation exposure only in certain circumstances
  • Physical injury
  • Burns
  • Panic, fear

RDDs can also include other means of dispersal, including placement of a container containing radioactive material to disperse powdered or aerosolized forms.

What Should We Look for?


In addition to Signs of Dangerous Mail (above) which can help an organization identify possible dangers, radiological threats will need the help of specialized equipment to detect radiation hidden in a mail package.

There are different types of radioactive materials that emit different kinds of radiation:

  1. Gamma and X-rays can travel long distances in air and can pass through the body exposing internal organs; it is also a concern if gamma emitting material is ingested or inhaled.
  2. Beta radiation can travel a few yards in the air and in sufficient quantities might cause skin damage; beta-emitting material is an internal hazard if ingested or inhaled.
  3. Alpha radiation travels only an inch or two in the air and cannot even penetrate skin; alpha-emitting material is a hazard if it is ingested or inhaled.

Do We Have the Correct Equipment for Protection?

A radiological mail threat can be detected with equipment which measures dose rate such as a Geiger counters. Systems to detect radiation in mail operations are capable of detecting and identifying differing types of radiation particles mentioned above (i.e. alpha, beta, and gama). Other types of instruments are used to identify the radioactive element(s) present.

Organizations can set up their own screening equipment at their own location. When cost of equipment and training is a factor, mail can be screened at a 3rd party offsite screening facility. With these “offsite mail screening” facilities, you have no capital costs and pay a monthly fee that is typically based on the volume of mail screened. (For the record, SoBran operates several of these facilities.)

How Can We Ensure Protection?

Best practices include:

  1. Screening inbound delivery vehicles for radiation using pedestal or wall mounted sensors.
  2. Integrating radiation sensors into the central security system – monitoring 24/7.
  3.  Equipping mail center personnel with wearable radiation pagers while screening and processing mail or unloading delivery vehicles in the loading dock area.

Basic steps to Radiological Mail Safety include:

1. Put a plan in writing

2. Install correct sensor equipment

3. Train employees

4. Run practice drills

If this is not possible, consider outsourcing mail screening to a third party or sending mail to a third party screening facility. Stay vigilant and next time we will cover the threat of explosives and letter bombs.

As always, I appreciate your comments.