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Homemade, Cheap and Dangerous
Terror Cells Favor Simple Ingredients In Building Bombs

By Craig Whitlock
Washington Post Foreign Service
Thursday, July 5, 2007

LONDON, July 4 -- The 39-page memo recovered from an al-Qaeda laptop computer in Pakistan three years ago read like an Idiot's Guide to Bombmaking. Forget military explosives or fancy detonators, it lectured. Instead, the manual advised a shopping trip to a hardware store or pharmacy, where all the necessary ingredients for a terrorist attack are stocked on the shelves.

"Make use of that which is available at your disposal and . . . bend it to suit your needs, (improvise) rather than waste valuable time becoming despondent over that which is not within your reach," counseled the author of the memo, Dhiren Barot, a British citizen who said he developed his keep-it-simple philosophy by "observing senior planners" at al-Qaeda training camps.

Barot, who was later captured near London and is serving a 30-year sentence, had envisioned an attack with multiple car bombs that would detonate liquid-gas cylinders encased in rusty nails -- a strategy with striking similarities to an attempt last week by a suspected terrorist cell to blow up three vehicles in London and Glasgow, Scotland.

Counterterrorism officials have warned for years that Osama bin Laden and his lieutenants have tried to obtain weapons of mass destruction, such as a nuclear device or chemical or biological weapons. In response, U.S. military and intelligence agencies have invested vast amounts of money to block their acquisition.

So far, however, al-Qaeda and its affiliates have relied almost solely on simple, homemade bombs crafted from everyday ingredients -- such as nail-polish remover and fertilizer -- when plotting attacks in Europe and the United States.

The makeshift bombs lack the destructive potential of the conventional explosives that rake Iraq on a daily basis. They are also less reliable, as demonstrated by the car bombs that failed to go off in London last week after the culprits tried to ignite them with detonators wired to cellphones.

But other attempts have generated plenty of mayhem and damage, including the kitchen-built backpack bombs that killed 52 people in the London public transit system on July 7, 2005.

"It makes no difference to your average person if somebody puts a car bomb out there that is crude or one that is sophisticated," said Chris Driver-Williams, a retired British major and military intelligence officer who studies explosive devices used by terrorist groups. "If it detonates, all of a sudden you've got a very serious device and one that has achieved exactly what the terrorists wanted."

The advantages of homemade explosives are that they are easy and cheap to manufacture, as well as difficult for law enforcement agencies to detect. According to one expert, the peroxide-based liquid explosives that an al-Qaeda cell allegedly intended to use to blow up nine transatlantic airliners last summer would have cost as little as $15 a bomb.

It is technically simple to make such explosives. Instructions are widely available on the Internet. Experts added, however, that it takes skill and sophistication to construct a viable bomb by adding timing devices, detonators or secondary charges.

Investigations have found evidence that most al-Qaeda cells involved in bombing plots in Europe have received training in camps in Pakistan or Afghanistan, or were tutored by graduates of those camps.

Among them: cell members involved in the July 7, 2005, bombings in Britain and a separate plot two weeks later that also targeted the London subway. The suspected ringleaders of the May 16, 2003, bombings in Casablanca were also al-Qaeda camp veterans who had experimented in explosives. Richard Reid, who tried to blow up an American Airlines flight from Paris to Miami in 2001, was taught how to build his shoe bomb in Afghanistan.

Stephen Swain, former head of the international counterterrorism unit at Scotland Yard in London, said the culprits in each case had been trained by seasoned al-Qaeda operatives "without a shadow of a doubt."

"It's a common thread throughout the entire theater of al-Qaeda-style operations," said Swain, who retired last year and is a senior consultant for Control Risks Group, an international security firm. "There's quite a lot of training going on in this regard."

Simple Recipes

Terrorist groups have been using homemade explosives for years. In February 1993, Islamic radicals drove a truck loaded with about 1,500 pounds of urea nitrate -- a fertilizer-based explosive -- and hydrogen-gas cylinders into a garage underneath the World Trade Center.

The bomb killed six people and injured more than 1,000. Investigators determined that the cell built the bomb in New Jersey by consulting manuals brought from Pakistan. Two years later, the ringleader of the plot, Ramzi Yousef, tried but failed to use homemade liquid explosives to down 11 airliners crossing the Pacific Ocean.

The same year, Timothy J. McVeigh blew up the Alfred P. Murrah Federal Building in Oklahoma City with a truck bomb consisting of 5,000 pounds of fuel oil and fertilizer, killing 168 people.

Since then, it has become more difficult to purchase large quantities of fertilizer without attracting attention; sellers in the United States and many European countries are supposed to notify authorities of suspicious customers.

The last known attempt by al-Qaeda to construct a fertilizer-based bomb in Europe came in 2003, when a cell operative bought 1,200 pounds of bagged Kemira GrowHow fertilizer for about $200 from an agricultural supply store in Britain. The salesman, John Stone, later testified that he thought the transaction was strange because it was the wrong time of year to apply the substance and the buyer claimed to have only a small garden plot.

"I hope you're not going around bombing anything," Stone said he told the buyer half-jokingly, although the salesclerk did not notify police.

British authorities were tipped off soon after, however, by an employee at a rental-storage center where the cell was keeping the fertilizer. In April, five members of the group were convicted in the plot, known as Operation Crevice. Many European fertilizer manufacturers have since reduced the amount of ammonium nitrate, a key bomb ingredient, in their products.

Partly as a result, European and U.S. counterterrorism officials said terrorist cells are increasingly turning to peroxide-based explosives, which can be made in much smaller quantities from materials available at drugstores.

The most commonly used compound is triacetone triperoxide, or TATP. Primary ingredients for a homemade batch typically include acetone, which can be found in nail-polish remover, and hydrogen peroxide, a chemical used in hair-bleaching products.

TATP wields about 85 percent of the explosive power of TNT and can be made in a kitchen or bathroom. A dime-size amount of the explosive can ignite a fireball the size of a basketball.

'Nobody Ever Stops Me'

The risky side of TATP is that it is highly unstable. A spark or light friction can detonate the explosive, making it extraordinarily difficult to handle. Experts and police said there have been numerous cases in which suspected terrorists -- as well as foolhardy amateur chemists -- have set off accidental explosions, resulting in death or severe injuries.

"You need to concentrate the chemicals," said Hans J. Michels, a professor of chemical engineering at Imperial College in London. "It's a filthy job and it's dangerous, but it can be done."

Despite the dangers, al-Qaeda cells have used peroxide-based explosives in more than a dozen plots in the past decade, including the July 7 and 21, 2005, London incidents, as well as attacks in Casablanca, Istanbul and the Indonesian island of Bali, according to counterterrorism officials. Danish police also discovered TATP in September during the arrest of seven terrorism suspects in Odense.

In crystalline form, TATP looks like powdered sugar and is difficult to detect in airports; security officials need to examine an exposed surface with a swab kit or other tester to determine its presence.

"TATP and peroxide-based explosives are concern number one for the aviation industry," said Ehud Keinan, a chemistry professor at Technion-Israel Institute of Technology and a leading researcher on the substance. "It will take some time before we are protected. Right now, we are not."

Reached by telephone in Paris, where he was scheduled to give a lecture about TATP on Wednesday at an international conference, Keinan said he often carries a small sample of the volatile compound in his carry-on luggage when he flies -- just to test airport security. "Nobody ever stops me," he said.

When asked if it might be dangerous to sit next to him on a plane, he said, "If you know how to take care of it, it's okay. If you don't know what you're doing, you're in trouble."

U.S. Homeland Security officials have said terrorism suspects arrested last August in Britain on charges that they were plotting to blow up several transatlantic airliners might have been planning to smuggle on board TATP or a related compound, HMTD, hexamethylene triperoxide diamine. Experts said it would take as little as one or two quarts of those explosives to down a large plane.

TATP was discovered in the late 19th century but was deemed to have no industrial or commercial applications because it was so unstable. Researchers generally ignored the substance until 1980, when Palestinian fighters used it for the first time in a bomb in Israel.

Palestinian bombers have used it ever since. TATP was used for the first time in an attack in Europe in July 1994, when Palestinians exploded a car bomb outside the Israeli Embassy in London.

U.S. and European counterterrorism investigators paid limited attention to the explosive until the July 2005 bombings in London. Afterward, the New York City Police Department built an exact replica of the apartment in Leeds, England, that the July 7 conspirators allegedly used to manufacture their backpack bombs.

Hugh O'Rourke, deputy inspector of the NYPD counterterrorism division, said the police department wanted to show beat officers what a kitchen-counter TATP production line would look like. He said it is easy to mistake the white powder and its cooking tools -- such as pool cleaners, large tubs or commercial-size fans -- for a common drug lab.

"Patrol cops see a lot of white powder, think it's crack, and want to touch it and package it," which could easily result in an explosion, he said. "We don't want them doing that."

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