"Since the masks are sold out in the United States, we received a huge order but our capacity is limited. We also have to respond to our clients in Chile," Jaime Lean, chief executive of Masprot, told Reuters this week.

The specter of a biological or chemical attack by the same groups suspected of masterminding the aerial attacks on the World Trade Center in New York and the Pentagon near Washington has led to a run by consumers in the United States on gas masks, guns and survival supplies.

While most Americans support President George W. Bush's declared war on terrorism targeting Saudi-born Muslim dissident Osama bin Laden, they fear this week's military strikes in Afghanistan may provoke further attacks on U.S. soil, this time with dreaded chemical or biological weapons.

HIGH QUALITY BUT USELESS

Chile's Masprot is one of the few Latin American makers of gas masks that boasts U.S.-approved quality certification.

But the company's own management said that they have limited benefit against a surprise chemical or biological weapons assault because the bulky and uncomfortable masks would need to be worn constantly to be effective.

They are intended to protect workers from toxic fumes in mining or in crop fumigation, Lean said.

Chilean military expert Francisco Le Dantec said the masks could help protect somewhat against an attack if authorities knew it was coming, an unlikely scenario.

"Nobody can live constantly wearing a mask. They go crazy," he said.

Moreover, the masks are not intended to protect against a bacteria like anthrax, for example, because it spreads gradually and cannot be foreseen, he said.

"In the United States, there is so much hysteria that the masks are being sold out. People remember the Gulf War when chemical attacks were also expected. But the truth is they are not much help," Le Dantec said.

Enrique Accorsi, president of the World Medical Association, agreed.

"The masks are useless (against a biological attack)," he told Chilean radio recently.

Despite the opinion of the experts, Masprot still hopes to clinch a deal with the U.S. gas mask importers and is awaiting an answer to its counter-offer.