FP Explainer

How Dangerous Is the Plutonium Leaking from the Japanese Nuclear Reactor?

Not as dangerous as the other substances it's releasing.

On March 29, Japanese officials announced that toxic plutonium had been detected in the soil surrounding the earthquake- and tsunami-damaged Fukushima Daiichi nuclear plant. The plutonium is thought to come from partially melted fuel rods in one of the plant's reactors. Tokyo Electric Power Co., which runs the stricken plant, maintains that the plutonium doesn't pose any threat to human health, but given the number of times the company has been caught downplaying the crisis over the last few weeks, it's understandable that the public would be skeptical. Isn't even a tiny bit of plutonium extremely dangerous?

Yes, but it's far from the biggest problem at Fukushima right now. We don't yet know exactly how much plutonium was detected in the soil near the plant, but it's unlikely to pose a serious health threat, particularly for those beyond the immediate vicinity of the plant. According to the International Atomic Energy Agency, the amount of plutonium detected does not exceed the levels normally tracked by Japanese authorities. Traces of plutonium are often found in soil around the world -- an unfortunate consequence of decades of nuclear testing -- and it's only because of the isotopic composition of this sample that authorities can say for certain it came from the damaged reactor.

Plutonium is scary stuff, largely because of how long it stays radioactive: The plutonium-239 isotope, among those used in one of the Fukushima reactors -- has a half-life of 24,000 years. However, the immediate dangers posed by plutonium exposure are often exaggerated. According to a 1995 report from the Lawrence Livermore National Laboratory, you would have to ingest about .5 grams of plutonium to die immediately, compared to about .1 grams of cyanide. The plutonium at Fukushima isn't in the air, but inhaling about 20 milligrams of plutonium would probably kill you within a few months. External exposure carries almost no risk.

It is possible that, down the road, plutonium inhalation could be a concern, but it's still a relatively small one. Inhaling 0.0001 milligrams of plutonium would increase the risk of cancer mortality from about 200 in 1,000 to 201.2 in 1,000.

But at the amounts and levels currently detected, it's unlikely that anyone will be inhaling even that much plutonium from the Fukushima leak. What about plutonium in the drinking water? It, too, is a relatively minor threat: Plutonium is a heavy element that does not dissolve easily in water. If 10 ounces of it were introduced into a reservoir, only about 3 milligrams (one part in 100,000) would be dissolved; the rest would settle into sediment. If, somehow, the entire 3 milligrams were ingested by a population, it would, in theory, only cause about 0.6 additional cancer deaths.

Plutonium may be grabbing the headlines right now, but it's not the most dangerous substance being emitted from Fukushima. The steam intentionally vented from the plant contains iodine and cesium, both of which have a far shorter half-life than plutonium, but are being released in much higher amounts and, being airborne, can travel much farther. Radioactive iodine-131 has been detected off the coast of Fukushima at levels 1,150 times higher than normal. These elements may not be quite as radioactive as plutonium, but if ingested or inhaled, they also pose a risk of causing cancer.  

The severity of Japan's crisis shouldn't be downplayed, but plutonium is not the element that should be keeping people up at night.

Thanks to John Lee, professor of nuclear engineering and radiological sciences at the University of Michigan.

YOSHIKAZU TSUNO/AFP/Getty Images

FP Explainer

Can Any Old Country Now Bomb Libya?

Technically, yes, thanks to a vague U.N. resolution. 

The governments enforcing the no-fly zone over Libya are currently deadlocked over who will coordinate the international effort. The United States and Britain are pushing for NATO to take over, while France is advocating a "political steering body" to manage the mission, in order to make sure that Arab governments remain involved (at least superficially).  Part of the problem comes from the vagueness of U.N. Security Council Resolution 1973, which establishes the no-fly zone, but avoids specifying which countries will lead or participate in its enforcement. So far, the mission has been led by the United States, Britain, and France -- with Canada, Belgium, Denmark, Italy, Norway, Spain, and Qatar also participating. But, in theory, could any country that wants to take it upon itself to enforce the no-fly zone?

Technically, yes. Security Council Resolution 1973 "authorizes Member States that have notified the Secretary-General, acting nationally or through regional organization and arrangements, and acting in cooperation with the Secretary-General to take all necessary measures ... to protect civilians and civilian populated areas under threat of attack in the Libyan Arab Jamahiriya." It goes on to prohibit a "foreign occupation force" on Libyan territory and "requests that the Member States ... inform the Secretary-General immediately of the measures they take pursuant to the authorization."

So if, say, Palau decided to start flying reconnaissance sorties over Benghazi this week there's nothing in the resolution to stop it. (This would admittedly be difficult, since Palau doesn't have a military.) The drafters of the resolution may have intentionally left this passage vague in order to avoid giving any one regional organization, such as NATO or the Arab League, responsibility for enforcing the resolution.

Moreover, the phrase "acting in cooperation with the Secretary-General" is vague enough so that member states wishing to participate in the military action don't actually have to get approval from Ban Ki-moon's office, they just have to inform him of their participation.

The vagueness of the resolution isn't particularly unusual for actions taken under the U.N. Charter's Chapter 7, which authorizes member states to use force in response to "threats to the peace, breaches of the peace, and acts of aggression." Resolution 678, which began the 1991 Gulf War, was actually even less specific, authorizing "Member States co-operating with the Government of Kuwait" to "use all necessary means to uphold and implement resolution 660." The Libya resolution at least asks that the secretary general be informed and places limits on the types of military action that can be taken and where.

As one might expect, member states often disagree on just what a Security Council resolution actually authorizes them to do. The United States and several allies read 678 as granting them authority to enforce a no-fly zone in Iraq after major combat operations had ended in order to protect civilians, an interpretation that was widely disputed at the time.

And in the Libya campaign, rifts are already beginning to show. U.S. and British officials were reportedly angered that France launched the first airstrikes against Libya without consulting them. And aside from two Qatari figher planes and a cargo jet that are currently en route, Arab countries are not participating to a significant degree, despite a paragraph in the resolution that specifically "recognizes the importance of the League of Arab States in matters relating to the maintenance of international peace and security in the region."

Not than anything's stopping more countries from joining in, should they want to.

Thanks to Micah Zenko, fellow for conflict prevention at the Council on Foreign Relations; Anthony Clark Arend, professor of government and foreign service at Georgetown University; Philip G. Alston, professor of law at the New York University School of Law; and Jose Alvarez, professor of international law at the New York University School of Law.