Pakarab's factories are hundreds of miles from the Afghan border, in the southern Punjabi city of Multan. The area is notorious for local militant groups with global aspirations, but Pakarab is a model of profit and efficiency. A household name for any farmer in Pakistan, the company is successful and widely respected, and trying to become the first Pakistani company to be listed on the New York Stock Exchange.
Pakarab produced 350,000 metric tons of calcium ammonium nitrate last year. But that's pretty much where everyone's knowledge ends. The company has not been required to track where the fertilizer goes after it's sold.
"That's where it gets difficult," said a U.S. official in Pakistan. "As of now, there's no regulation after that point."
Pakistan's interior ministry -- which declined multiple requests from ABC News for an interview -- has created a counter-IED strategy designed to identify buyers and track the movement of CAN. But the plan is a huge undertaking in a country where rule of law infrastructure is weak: despite suffering from some of the worst terrorism in the world for the last 10 years, Pakistan's courts have not convicted a single terrorist since 9/11.
The interior ministry and the U.S. embassy in Pakistan are working together to create better laws and train police and prosecutors to try and convict militants who create IEDs; better track where the fertilizer goes by registering sellers and tagging bags with the same "No Objection Certificates" that diplomats are required to carry; and, at the last stage, strengthen the checks made on the roads leading into Afghanistan. Pakistani officials have even spoken of creating "restriction zones" where CAN would be banned a certain distance from the Afghan border.
But the U.S. official in Pakistan said those efforts are in "very draft form."
In the U.S., "we take it for granted that there's a working police force, that the courts work… and if you make it a priority and stay focused, you can eradicate," says Casey. "I wonder sometimes even with a full commitment, how able would they be to execute their plan, given their institutions?"
It's also not clear how quickly the plan to step up regulation of CAN is being implemented. Pakarab said in a statement provided to ABC News it had not yet been told by authorities to track sales of the fertilizer.
"The Government of Pakistan has not mandated that the fertilizer be tracked after it leaves the factory," a company spokesman said in the e-mailed statement.
But the company said it has been working with both "the Pakistani and U.S. governments to make the product safer and identifiable. As an initiative from the company's side the packaging for CAN fertilizer has already been made distinguishable for easy detection."
Pakarab has also tentatively agreed, according to a separate U.S. official, to dye CAN a shade of yellow so it can be easier detected at the border and identified if found in a bomb in Afghanistan. Pakarab said it has been testing a dye, but would not confirm it had made any decisions. Initial tests "are encouraging and lab testing and in house development of more samples is underway," the company spokesman said. "This is likely to assist in quick detection and traceability."
It is not clear how Pakarab's 2,500 retailers, or Pakistan's large agricultural landowners -- some of the country's most powerful people -- will react to strange-looking fertilizer once it is sold widely in Pakistan.