A series of contracts have been uncovered that relate to the US army's Dugway Proving Ground in Utah. They ask companies to tender for the production of bulk quantities of a non-virulent strain of anthrax, and for equipment to produce significant volumes of other biological agents.

Issued earlier this year, the contracts were discovered by Edward Hammond, director of the Sunshine Project, a US-German organisation that campaigns against the use of biological and chemical weapons.

One "biological services" contract specifies: "The company must have the ability and be willing to grow Bacillus anthracis Sterne strain at 1500-litre quantities." Other contracts are for fermentation equipment for producing 3000-litre batches of an unspecified biological agent, and sheep carcasses to test the efficiency of an incinerator for the disposal of infected livestock.

Major concern

Although the Sterne strain is not thought to be harmful to humans and is used for vaccination, the contracts have caused major concern.

"It raises a serious question over how the US is going to demonstrate its compliance with obligations under the Biological Weapons Convention if it brings these tanks online," says Alan Pearson, programme director for biological and chemical weapons at the Center for Arms Control and Non-Proliferation in Washington DC. "If one can grow the Sterne strain in these units, one could also grow the Ames strain, which is quite lethal."

The US renounced biological weapons in 1969, but small quantities of lethal anthrax were still being produced at Dugway as recently as 1998.

It is not known what use the biological agents will be put to. They could be used to test procedures to decontaminate vehicles or buildings, or to test an "agent defeat" warhead designed to destroy stores of chemical and biological weapons.

Highly provocative

There are even fears that they could be used to determine how effectively anthrax is dispersed when released from bombs or crop-spraying aircraft. "I can definitely see them testing biological weapons delivery systems for threat assessment," says Hammond.

Whatever use it is put to, however, the move could be seen as highly provocative by other nations, he says. "What would happen to the Biological Weapons Convention if other countries followed suit and built large biological production facilities at secretive military bases known for weapons testing?"

A spokesperson for Dugway said the anthrax contract is still at the pre-solicitation stage, and the base has not yet acquired the agent. They refused to say what it will be used for.