But one of the concerns is insider threats, you know, someone who works there. Because this fall, in October, for steel coil, police who were doing a drug raid on a mobile home near Los Alamos National Lab in New Mexico found some classified material. He has something like 40 years experience doing national security. He was in the Reagan White House. He led the negotiations of the START nuclear arms reduction treaty. And there's widespread speculation that there are also personality conflicts going on. There are certainly a lot of people who are sad to see him go. CHADWICK: Reporting for the NPR Science Desk, David Kestenbaum. David, thank you again.

And it turns out this woman - the woman who worked there, her job was to basically scan these classified documents and put them in a database, had brought some of the stuff home. Some of it was in electronic format. And the lab has now put glue in the USB ports on its computers to prevent this from happening again. But I interviewed the lab's director, Michael Anastasio, after this incident. And he saw the problem as, look, someone just broke the rules.

 And replacing the guy at the top is going to fix that? KESTENBAUM: Well, I have to say, there are a lot of people outside and inside, I think, who feel that Linton Brooks is the one who should have been doing the firing and not the guy who should have been fired.

You know, yes, this was bad but this woman was trained and she shouldn't have brought this stuff home. So he didn't necessarily see it as a problem of, you know, we had bad security, as much as it is that someone just broke the rules.