Herrera’s interpretation of events seemed extreme, but after my failure at CIEMAT, I had no additional information and few Spanish contacts. The next day, after a tour of Palomares—an incongruous town somewhere between a peasant village and a middle-class British holiday resort—we returned to José’s house. By this point, he trusted me enough to download several hundred DOE documents onto my laptop. He had gotten these files from the DOE Web site, and I was embarrassed that I hadn’t been able to find them myself. But when I returned to the U.S. and typed in the links José had shown me, they were all dead. It’s unclear whether José had retrieved the documents years ago, before the post-9/11 reclassification effort, or whether the DOE had blocked parts of its Web site within the U.S. only. Regardless, despite many attempts over the next two years, I was never able to access these links from my computer.

But thanks to José, I already had the goods. I painstakingly pored through his documents until I hit paydirt. Buried among the memos and letters spanning forty years were some damning tidbits. One 1998 memo paraphrased DOE and CIEMAT scientists discussing plutonium contamination and the location of “pits.” “Important to recognize that Pu [Plutonium] was left at the site,” Spanish scientist Emilio Iranzo is cited as saying. “There were not enough drums to take all the Pu away.” The memo proved that American and Spanish officials had known about the buried debris and excessive plutonium for at least ten years before the information was exposed in the press. I had found my cover-up.

After my visit, someone within CIEMAT began leaking information to a reporter at El País. I’m not sure if my investigation prompted this new openness, but new revelations about Palomares began to appear in the paper every few months. The Spanish government is now finalizing the expropriation of twenty-one hectares (about fifty acres) of contaminated land around area #2, to prevent a British company from developing it into a golf resort. And, to compensate the people of Palomares for their suffering, the government has tentative plans to build a theme park in the area. One section of the theme park will showcase the era of nuclear technology, and feature the shell of an American B-52.

My book, The Day We Lost the H-Bomb: Cold War, Hot Nukes, and the Worst Nuclear Weapons Disaster in History, was published last year.

Of the FOIA requests I filed over the course of my research, about half were ultimately filled after long delays; the rest were, as far as I can tell, simply ignored. Without money to hire a lawyer, I had no recourse when government officials chose to sidestep the law. For one important request I got Senator John Kerry’s office involved, but despite the efforts of his staff, that request was filled only in November 2009, more than five years after I filed the original request and seven months after my book was published. To be fair, without FOIA I may have never received any of these documents. But for me, it worked only when I was lucky and persistent—and had lots and lots of time.

However, I also learned that there is often a back door to access this kind of information. The U.S. government is a vast, somewhat sloppy organization. Some documents I couldn’t get through FOIA I found in boxes and basements. Many people I interviewed gave me papers and photographs that I couldn’t get from the U.S. government. Two retired Navy divers, for instance, loaned me publicity photos taken during the recovery that had since disappeared. A retired Sandia engineer with an ax to grind gave me a CD full of maps and memos. Once, a friendly FOIA manager pasted a personal note onto a formal letter, advising me to look for a particular document outside official channels. (Unfortunately, her advice led me to the Sandia archives and a dead end.) And, of course, my documentary filmmaker in Spain gave me a treasure trove of DOE files.

Barbara Moran is a science journalist in Boston. Her first book, The Day We Lost the H-Bomb: Cold War, Hot Nukes, and the Worst Nuclear Weapons Disaster in History, was published by Presidio Press, an imprint of Random House, in 2009.