The Comprehensive Test Ban Treaty Organization (CTBTO) announced on April 23 that its International Monitoring System (IMS) detected radioactive isotopes consistent with the February 12 North Korean nuclear test and announced the discovery on April 23, 2013. The radionuclide station in Takasaki, Japan detected xenon-131m and xenon-133, two radioactive isotopes that are associated with nuclear fission.

The gases detected by the Takasaki station, located approximately 620 miles from the North Korean test site, were produced by a nuclear fission event that occurred at least 50 days before detection. The IMS was able to identify the North Korean test site as a possible source for the noble gases.

At an April 11 event hosted by the Arms Control Association, Senator Jeanne Shaheen and Lt. Gen. Frank Klotz (USAF, ret.) urged U.S. ratification of the CTBT. Shaheen noted that ratification of the CTBT will require a great deal of preparation, "But that just means we should start now to chart a path forward for its eventual consideration."

Klotz reiterated his support for the CTBT, saying "the logic for moving forward and ahead on ratification of the CTBT is inescapable." He went on to say that the United States already abides by the requirements of the treaty and is unlikely to resume nuclear testing. Therefore, the United States should gain the full benefits of the CTBT by ratifying the treaty, which would allow it to "rally international pressure against would-be proliferators" and "constrain regional arms races."

Senator Tom Udall of New Mexico and a bipartisan group of senators reintroduced the Radiation Exposure Compensation Act (RESA) Amendments of 2013 on Friday, April 19. Representative Ray Lujan of New Mexico introduced companion legislation in the House of Representatives the same day.

This legislation would go beyond previous bills by extending compensation to uranium workers who were employed after December 31, 1971. It also makes all claimants eligible for medical benefits and the maximum compensation of $150,000, and funds an epidemiological study of the health effects of uranium workers and their families, as well as residents near uranium production sites. In addition, the RECA Amendments 2013 expands the recognized downwind areas to include Arizona, Colorado, Guam, Idaho, Montana, New Mexico, Nevada, and Utah.

Christine Wing, a Senior Research Fellow at the Center on International Cooperation at New York University, sat down with the CTBTO to discuss her experience working on nuclear disarmament during the Cold War and how civil society can advance the cause of disarmament today, and particularly how it can help achieve the entry into force of the CTBT.

Wing stressed the importance of the CTBT's entry into force in stemming proliferation. She stated that a legal ban on nuclear testing would not only prevent horizontal proliferation-the development of nuclear weapons by non-nuclear states-but would also prevent vertical proliferation by inhibiting nuclear-weapon states ability to make qualitative improvements in their nuclear arsenals. Additionally, Wing also pointed to the indirect effects of the CTBT, such as the treaty's ability to deemphasize the role that nuclear weapons play in national security policies.