Intelligence data pulled from websites

US Army chemical depot: Details no longer on the web

Sensitive documents and reports have been pulled from websites across the internet following the 11 September attacks due to fears the information could be useful to terrorists.

Several US Government sites have removed information about hazardous chemicals and maps out of concern the data could prove useful to people planning further attacks.

Even private websites have taken down details about military bases and intelligence offices.

But government watchdogs warn that national security could be used as a pretext to keep information from the public.

Chemical risks

People have a right to know what kinds of risks there are, but unfortunately terrorists are people, too

Jim Makris, EPA emergency coordinator

Much of the information that has disappeared from official US websites relates to hazardous chemicals. The Environmental Protection Agency has removed pages on chemical plants and their emergency response plans.

"People have a right to know what kinds of risks there are, but unfortunately terrorists are people, too," said Jim Makris, the EPA's emergency coordinator.

The Department of Health and Human Services pulled a report on the dangers of chemical plant terrorism.

And the Centers for Disease Control and Prevention has taken down a report about the lack of preparedness against a terrorist attack using poison gas or other chemical agents.

Sensitive geography

Other data that has been removed relates to information that could help enemies of the US identify targets and plan attacks.

Recent events have focused additional security concerns on critical infrastructure systems

Office of Pipeline Safety

The National Imagery and Mapping Agency has suspended all sales of maps of military installations as well as the highest-resolution maps of other US locations.

The Geographic Information Services, which provides detailed maps of roads and utilities, is limiting access to its database to officials.

And the Office of Pipeline Safety (Oops) within the Transportation Department has adopted a similar tack, limiting access to its national mapping system for a variety of pipelines to officials.

"Recent events have focused additional security concerns on critical infrastructure systems," said a note on its websites.

"Due to these concerns, the [Office of Pipeline Safety] no longer provides unlimited access to the internet mapping application, pipeline data, and drinking water unusually sensitive area data."

Intelligence data

Private websites taken similar action, in case they could unwittingly aid terrorists.

Concerns over chemical warfare

The Federation of American Scientists, which maintains a detailed database of government and military information, has removed hundreds of pages from its website.

It has taken down data on the location and layout of intelligence offices, as well as details on chemical weapons facilities.

"We need to take a moment to assess the new security environment," said Steve Aftergood of the FAS.

But some freedom of information advocates have expressed concerns that national security could be used to suppress politically sensitive reports.

"While security may improve, the spirit of civil society is lost. We cannot let that happen here," said Gary Bass of OMB Watch, a US group that campaigns for freedom of information.

Some security experts have questioned the effectiveness of removing potentially sensitive material from official sites at this stage.

They say much of the material which is now unavailable could have been previously downloaded and saved on users' hard drives.

Some of the reports are still available in public libraries or can be found on unofficial websites.