The early April discovery of radioactive material in the Mayapuri industrial area of West Delhi has sent a chill through Indian security authorities. Although it has finally been determined that gross carelessness rather than terrorism was behind the incident, officials are concerned that publicity about the incident may have given food for thought to terrorists.

The incident is emblematic of India's lax enforcement of radioactive waste-disposal laws at a time when the threat of nuclear terrorism is a growing concern, especially given the audacity of the attacks on Mumbai luxury hotels and the train station in November of 2008 that took 180 lives. The leak came to light a week before the Nuclear Security Summit in Washington, DC. A number of officials at the conference went on record expressing fears that terrorists could use weapons of mass destruction such as the sowing of nuclear waste without actually building a bomb.

The radioactive material, later identified as cobalt-60, apparently first arrived at the shop of a scrap dealer in the industrial area on March 12. The scrap dealer and eight others were hospitalized. The first – and so far only -- death in this case took place some six weeks later when the scrap dealer died of radiation poisoning. It was not until April 5 that that the radiation source was discovered.

As officials from the National Disaster Management Authority (NDMA) and Bhabha Atomic Research Centre (BARC) got involved in unravelling the mystery, murkier scenarios were considered. The immediate concern of the Indian authorities was the timing of the incident in a city that is less than five months away from hosting the Commonwealth Games. The questions that were tossed about in security circles were: was the Mayapuri incident a low-key testing operation? Was it a dry run for a large-scale nuclear, biological and chemical (NBC) strike or a dirty bomb attack by jihadists?

The investigations ended in an anticlimax and no terror angle was found. The origin of the cobalt-60 was traced to Delhi University's chemistry department, where it had been lying unused for 25 years. The Cobalt-60 was in a "gamma irradiator" which was bought in 1968 from Canada and had not been in use since 1985. It was bought by scrap dealers in Mayapuri through an auction in February 2010. The scrap dealers dismantled the equipment and in the process, the lead covering on it was peeled off leading to radiation exposure. With this in mind, the Indian government is now seeking to tighten the rules on scientific handling of radioactive materials. Cobalt-60 is used for medical radiotherapy and industrial radiography among other things.

But the damage has already been done with Delhi University's carelessness. Publication of the Mayapuri incident, security personnel feel, has given an idea to terrorists. The National disaster management team has already held a series of closed-door meetings with sleuths and NBC warfare experts to thrash out a plan of action in case ultras try to unleash radiological terrorism. A top NDMA official this writer spoke to said the NDMA is leaving nothing to chance on this score.

Terrorists can strike in any of the following manners, and more:

Substances like cobalt-60 and cesium-137 can be made to reach the scrap markets in a bigger, planned manner. Such substances are readily available in virtually every country in the world as they have legitimate medical, commercial and industrial uses. The International Atomic Energy Agency (IAEA) has gone on record to warn that such radioisotopes are almost certainly not beyond the reach of even moderately capable non-state actors.

Such substances can be used in powdered form and thrown into the air or mixed into drinking water supply at the targeted venue (say, in one of the stadia during the Commonwealth Games in October 2010) with catastrophic results. The radioactive material in the Mayapuri incident was in metallic form and thus the clean-up operation was easier for the authorities.

Nonetheless, the find was chilling. The authorities are maintaining total secrecy about their plans and preparations for dealing with the NBC threat from terrorists during the New Delhi Commonwealth Games – and understandably so.

The radiation leak came to light just about a week before the Nuclear Security Summit in Washington. From the point of view of the international community, the larger question is not whether a dirty bomb attack can happen but why it hasn't happened yet.