And storage is a cinch: It takes up about as much space as a typical washing machine.

With growing fears of a biochemical attack, many biotechnology firms have waded into the uncertain science of prevention and detection of biological and chemical agents.

But a Maryland manufacturer has discovered a less-crowded market in homeland security: decontamination.

'We were a garage-shop operation a year ago,' said TVI chief executive Richard Priddy. Now, it cannot keep up with orders for its line of rapidly deployable decontamination shelters.

Its brochure reads like an L.L. Bean - an outdoor specialty items and clothing retailer - catalogue from Armageddon.

There is the Chem/Bio Infection Control System, an airtight tent fitted with filtration systems to remove toxic agents from exposed people.

There is the Casualty Management Shelter, an open-air shelter with a chemical-resistant exterior to protect the injured inside. And there is the Temporary Morgue, an all-weather structure for cold storage of cadavers.

But TVI's flagship product is the High Throughput Mass Decontamination Shelter, a carwash-like structure for humans with at least 50 shower nozzles threaded into its vinyl interior, a hot water pump and soap dispensers.

It is designed to be attached to a fire hose and has at least three shower lanes to separate men, women and the incapacitated after an attack.

The product is designed for particular situations.

If a 'dirty' nuclear bomb is detonated or a biochemical agent is released, for example, people fleeing the scene before being decontaminated would risk exposing others to the danger.

The shelters would be used to rapidly contain the threat. Carried in a pickup truck, the collapsible structure can be shuttled to the scene.

Ideally, TVI and local health officials say, the shelters would be placed at the scene and outside nearby hospitals to prevent patients from contaminating emergency rooms.

That's the plan in Massachusetts, the first to adopt the technology statewide. Local fire departments now have enough decontamination shelters to equip the state's 77 general admission emergency rooms after an attack. Each of the 15 fire districts also has a shelter to place on the scene of an attack.

'It takes one person who comes into a hospital with the wrong thing on them, and you lose it as a resource,' said Mr Stephen Clendenin, the deputy director of fire services in Massachusetts, who specialises in hazardous materials.

The shelters operate on a simple principle.

'You just cream people with water,' said Mr Thomas Gibson, a lieutenant with the hazardous material team at the National Institutes of Health (NIH) campus in Bethesda, Maryland.

The NIH, which built its own shower system, bought TVI shelters to create undressing and dressing stations for victims.

'When you take their clothes off, you take away 90 per cent of the problem,' Mr Gibson said. After that, the work of decontamination is washing exposed body parts, generally the head, neck and hands, he added.

The cleanser of choice in these high-powered shelters is baby shampoo. The no-tears formula is considered strong enough to remove most pathogens from the human skin without temporarily blinding patients.

'Decontamination is the same whether you are talking about chemical, biological or radiological agents,' said Mr Clendenin, the Massachusetts fire official. 'Soap and water is never a bad thing.' --The Washington Post