Stephen Leather - The Bombmaker

'Pounds,' said Andy. Ireland used the metric system but she'd been born in Belfast, in the north of the country, and most of the time she still thought in pounds and ounces, miles and gallons.

'So we have just over three thousand pounds of ammonium nitrate fertiliser. Will that be enough?'

Andy shook her head, trying to clear her thoughts. 'What?'

'Please try to focus, Andrea,' said Green-eyes. 'We don't have all day.'

'It depends.'

'On what?'

Andy shook her head again. It was all too much for her to take in. She put both hands up to her temples and massaged them, it's complicated.'

'I appreciate it's a complicated process, Andrea. That's why we need you.'

Andy cupped her hands around her chin. 'Where are you planning on building it?'

'That's none of your concern.'

'Yes it is. That's what I mean about it being complicated. You need pure ammonium nitrate, but you can't buy it in Northern Ireland. At least, you can buy it, but it's not pure. The government's not stupid – they know what the pure chemical can be used for, so in Ireland you can only buy it mixed with other stuff. Bonemeal, potash, the sort of stuff farmers need. The pure stuff isn't for sale to the public, and if you order it, you'll be checked out. So if you're building it in Northern Ireland, you've got to buy tons of common-or-garden fertiliser and boil off the impurities. It would take for ever to get two tons of pure ammonium nitrate.'

'What about in the UK?'

'That's different. Is that what you're planning? A bomb here in England?'

The woman ignored Andy's question. 'How much would we need? Is three thousand pounds enough?'

Andy tried to concentrate. A four-thousand-pound fertiliser bomb. The fertiliser accounted for eighty per cent of the mixture. Eighty per cent of four thousand. Three thousand two hundred. She nodded. 'That should be okay, give or take.'

The woman pointed at the far corner of the factory with her pen. Andy turned her head to look. A green tarpaulin covered a mound almost three feet tall. Next to the mound were a dozen large conifers in black plastic pots and several boxes of smaller plants. 'You can check it yourself later. What else?'

'Hang on,' said Andy. 'You can't just use it straight from the sack. It's got to be prepared.'

'And how do we do that?'

'Even if it's sold as pure, there'll still be some impurities and you've got to get rid of them first. You have to mix it with alcohol, then strain off the liquid.'

'So how much alcohol will we need?'

Andy did the calculation in her head. 'Assuming you reuse it a few times, a hundred gallons or so. The more the better. It's got to be denatured alcohol. It's used as paint thinner or antifreeze.'

'Where do we get it from?'

'Any biggish paint suppliers should have some.'

'What would happen if we didn't use the alcohol?'

'It might not go off.'

The woman nodded. 'What equipment will you need, to purify the fertiliser?'

'Large containers. Plastic or glass. Stirrers. Wooden or plastic. Then something to heat the mixture. Electric woks are good.'

'How many?'

'The more you have, the faster you can process it. Every pound of fertiliser has to be mixed with alcohol, then heated for three or four minutes. Say you do five pounds at a time. Three thousand pounds could take a full two days, working around the clock.'

'Two days?'

'It's a big job. You don't seem to understand how big a job it is.'

'So, if we can get six woks going, it'll take eight hours?'

'That's right. But it's hard work. And you have to have someone stirring all the time. It's a sort of stir-fry job, you know.'

'So, four. There'll be four of us, so four woks. What else?'

'Electric coffee grinders. I'd get four of them, too.'

'Four it is.'

Andy sat back and folded her arms. 'What are you going to do with it? The bomb?'

'That's not your concern.'

'Well, it is, sort of. There are different mixtures for different effects.'

'Whatever's most effective. Whatever'll give us the biggest bang, okay?'

Andy wanted to lie, to give her wrong information or to withhold something vital, something that would render the explosive inert, but she couldn't risk it. She didn't know how much they already knew. This could be a test, and if she failed the test it could be as dangerous as refusing to cooperate. She nodded slowly. 'Aluminium powder,' she said. 'You'll need about six hundred pounds.'

'Where would we get that from?' asked the woman.

'Paint suppliers again,' said Andy. 'The best sort to ask for is pyro grade 400 mesh.' She was surprised how easily the technical terms came to her. It had been years since she'd even thought about the components of a fertiliser bomb. The information belonged to another life, a life she had long ago walked away from.

'It's easy to get?' asked Green-eyes. 'There's not a register or anything?'

Andy shook her head. 'It's got too many uses. No one checks. But you'd be better buying it through a front company, something with decorator in the letterhead. And with that sort of amount, you might be better getting it from several different suppliers.'

"What about the alcohol?'

'It's got lots of legitimate uses, too. I'd buy it from several sources, though.'

The woman scribbled on her pad again.

'Sawdust,' said Andy.

'Sawdust?'

'As fine as possible. Two hundred pounds. Any sawmill will sell it to you. You can say it's for a pet shop. That's what we used to do. And detergent. Sodium dodecyl benzenesulphonate.' She spelled out the words slowly. 'A chemical supplies company will sell you the pure stuff. But almost any soap-based washing powder will do.' The information was all still there, she realised. It always had been, and probably always would be. A shopping list of death, imprinted somewhere in her neural pathways.

'How much will we need?'

'Thirty pounds or so.'

'And?'

'That's it,' said Andy. 'Ammonium nitrate, aluminium powder, sawdust and detergent. You can add diesel oil if you want. It's not vital, but it helps.'

'How much would we need?'

'Ten gallons or so.'

'And what equipment are you going to need?'

'Desiccators.'

'Desiccators?'

'To dry out the fertiliser. It absorbs moisture, and as soon as it's damp it's useless.'

'Are they easy to get?'

Andy shrugged. 'Depends. You might have to order one.'

'Is there anything else we could use?'

'An electric oven. And baking trays, a couple of inches deep.' Andy did a quick calculation in her head. 'One oven will dry about four hundred pounds a day. So it'll take you about eight days working around the clock to do it all.'

'And if we get four ovens – two days, is that right?'

Andy nodded.

'Okay. What else?'

'Respirators. Protective glasses. Overalls. Gloves. Plastic gloves and oven gloves, too.' She steepled her fingers under her chin and furrowed her brow as she thought. It had been a long time. A long, long time, and she wasn't sure if she'd remembered everything. She ran through the processes in her mind. 'Thermometers. Metal ones. And a tumble-drier,' she said. 'Two would be better.'

'This isn't an ideal home exhibition,' said the woman.

'It's for mixing the fertiliser and aluminium powder,' said Andy. 'It's got to be well mixed. We used to pack it in Tupperware containers then put it in a tumble-drier for half an hour or so.'

The woman nodded. 'Innovative,' she said.

'We had to be,' said Andy.

'How many?'

Andy thought for a few seconds. 'Two should do it.'

'Anything else?'

'That's all for the explosives. But the skill is in the preparation. You can't just throw it together.'

'And once we've made it, it's not unstable?'

'You could smash a train into it and it wouldn't go off. In fact, it's only good for a week or so. Maybe two weeks, but after that the fertiliser will have absorbed water again and no matter what you do to it, it won't go off. So you'll need lots of Tupperware containers, the bigger the better. And lots of black plastic rubbish bags. The more you wrap the stuff, the longer it'll take the water to penetrate. And you'll need bags to pack the finished product in. Hundreds of black bags.'