To Tom and most everyone else, Agent Orange was a different thing from PCBs. But the underlying problem was the same, and I'd have to explain how in a press release. Just another goddamn thing to get working on. This was turning into a paper-shoveling operation, more time spent at my desk than on my Zodiac.

If this was the kind of house that had napkins, I'd have sketched it out for Tom. But Tess, Laurie, and Ike were all recycling maniacs and I usually had to wipe up spills with my shirt sleeves. Cloth towels were very nice if you had someone doing your laundry for you, but they sucked when all you had was a washing machine with a bumed-out engine, and a landlord who filled the basement with water whenever he laid hands on a pipe wrench.

"I want you to explain all this shit to me anyway," Tom confessed.

"Okay, first of all, the bad thing about Agent Orange wasn't the Agent Orange. It was an impurity that got into it during the manufacturing process: dioxin. That's what you had, dioxin poisoning. But dioxin is just a shortened version of the full name. The full name is 2,3,7,8-tetrachlorodibenzo-p-dioxin. Also known as TCDD."

"This doesn't mean shit to me, man."

"Just hang on. TCDD belongs to a class of similar compounds that are known as polychlorinated dibenzodioxins."

"And that's related to polychlorinated biphenyls?"

"More or less. In both cases you've got a bunch of chlorine atoms, which is why it's called polychlorinated, and an organic structure that they're carried around on. In one case it's a biphenyl, in the other case a dibenzodioxin. You know what a benzene ring is? Ever take any chemistry?"

"No."

I looked around for six similar objects I could arrange in a ring. Of course, they were right in front of me. "A benzene ring is a six-pack of carbon atoms. The six-pack is held together with this little plastic holder. That's like a benzene ring. It's stable. It's strong. The six-pack stays together. It takes some effort to pull one of the cans away. There's a couple different kinds: benzenes and phenyls. Both six-pack holders, but the phenyl has one less hydrogen atom."

"Okay."

I went and pulled another six-pack out of the fridge. "If you put two six-packs together, you have a twelve-pack. If the six-packs are phenyls, then it's called a biphenyl. If the six-packs are benzenes, it's a dibenzodioxin-because the connection between six-packs-is made by using a couple of oxygen atoms. But it's basically similar to a biphenyl. So polychlorinated biphenyl and polychlorinated dibenzodioxin are structurally similar compounds."

"So these six-pack things, they're the toxic part?"

"No. The toxic part is the chlorine. That's what gets you."

"Well, shit, you should get chloracne from being in a swimming pool then, right? That's full of chlorine. Hell, drinking water's full of chlorine."

"Yeah. That's why half of the people in GEE drink spring water. Because they've heard about chlorine and don't know shit about chemistry."

Tom noticed the saltshaker on our table, laughed, and dumped a little salt out onto the table. "Shit, man! Sodium chloride, right? Isn't that in seawater? Hey, maybe that's why I got sick. It wasn't Agent Orange at all, man, it was the sodium chloride in that seawater."

"Okay, you're asking me: why is chlorine so incredibly toxic in dioxin and not in table salt?"

"I guess that's what I'm asking."

"Two reasons. First, what it's attached to. That biphenyl or dibenzodioxin structure-the twelve-pack-dissolves easily in fat. Once it gets into your body fat, it never leaves."

"That's what they said about the Agent Orange, that it sits in your body forever."

"Right. That's the first bad thing. The second bad thing is, the chlorine there is in covalent form, it's got the normal number of electrons, whereas the chlorine in salt is in ionic form. It's got an extra electron. The difference is that covalent chlorine is more reactive, it has these big electron clouds that can fuck up your chromosomes. And it slips right through your cell membranes. Ionic chlorine doesn't-the cell membranes are made to stop it."

"So the six-packs are like the vehicle, the gunboat, and the chlorines are like the soldiers with the machine guns who ride on it."

"Yeah, and the electrons are their ammunition. They ride up and down the river-your bloodstream-and slip into your cells and shoot up your chromosomes. The difference between that and table salt is that table salt is inorganic, ionic chlorine-soldiers without a boat, with no ammunition-and this other stuff is organic, covalent chlorine-bad stuff."

Tom sat back, raised his eyebrows. "Well then, if you think I'm going to go down there, forget it."

"Look, that's fine, and I don't blame you, but let me just say that I'm as paranoid as anyone and I went down there. I'm pretty sure we can do this without getting contaminated."

"I'll do other diving but I won't go to the bottom. I got enough of this shit in my body already."

"Fair enough."

I phoned Esmerelda. After this was over we'd have to give her an honorary membership in the group. If GEE was like the Starship Enterprise, then I was Scotty and she was Spock.

We had an extremely pleasant chat about her granddaughter's brand new pink dress, which had involved roughly a hundred man-hours of shopping, and about the weather and the Sox. Standing in the library, she spoke quietly, and I always found my own voice dwindling to a whisper during these conversations. It was like talking to an important Japanese warlord. You had to hem and haw and nibble around the edges for a few hours, just to be polite, before you got to the point.

"There's some kind of intern working there, a woman, working with The Weekly?'

"Yes. She had a little trouble threading the microfilm machines but now she's doing just fine."

"If someone ever invents a self-threading microfilm machine, half you guys are going to be out of a job. No offense to you."

"How can I help you, ST.?"

"If that woman comes up with anything really interesting, could you shoot me a copy?"

"About Mr. Fleshy?"

"You know it."

"Anything in particular?"

"Oh, I don't know. Something with photos in it. That always makes them nervous. Would you mind?"

"Certainly not. Is there anything else?"

"No. Just wanted to see how you were doing."

"Have fun, ST." That's how she always said goodbye to me. She must have some queer ideas about my job.

The next day we organized, and the day after that we did it. With another diver from the Boston office I swam around scooping muck into sample jars. We'd hand them off to Tom, who'd relay them up to the Zodiac, where Debbie was waiting. That way we wouldn't have to decompress every time we had a full load of samples. Debbie was our navigator, using landmarks on shore to judge our position and mark down roughly where each sample came from. We could plot the results later on. If the PCB concentration increased sharply in one direction, that would give us a clue as to where the source was. If we were really lucky, we'd be able to track it down, probably to a few barrels on the bottom.

The ultimate success would be to find some barrels with PCB still in them, and to get some photos. We couldn't salvage them ourselves, but the EPA probably could and, more important, they probably would. We could save the Harbor a lot of grief and we might find evidence that would lead us to the criminals.

I didn't want Debbie sitting out there alone on a Zodiac. We knew the Poyzen Boyzen people had a boat, and they seemed to know a hell of a lot about who we were and where we hung out. So we looked through our donor list and found a couple of yacht owners, then convinced them that it really would be fun to spend a day bobbing around in the Harbor, showing the flag. We hoisted another Toxic Jolly Roger, persuaded Tanya's black-belt squeeze to join up, and ferried a few media people out from Castle Island Park. Rebecca came, as did the starving freelancer and the reporter from the Globe. So far it was background.