RICHLAND -- There will be no cruising around the Internet or checking e-mail today at Pacific Northwest National Laboratory.

Computer screens are going largely dark.

It's a reminder to employees of the importance of maintaining computer security after some employees fell for a trick to download fake "malware," or malicious software, as part of an audit of the lab's cybersecurity.

The national lab in Richland plans a computer stand-down today. Employees will spend much of the day in training sessions -- in which they will be allowed to use their computers -- and in meetings to learn how and why to protect the lab's computer systems from intruders.

"This allows management and staff to have uninterrupted focus on understanding the need for a solid cybersecurity system at PNNL and on the responsibility that each individual employee has to ensure the network is safe," said Mike Talbot, a Department of Energy spokesman.

Shutting down much of the computer system is intended as "kind of a wakeup call," said lab spokesman Geoff Harvey. It will demonstrate how work at the lab would have to be done if a cyberattack were successful, he said.

The lab does classified work for the Department of Homeland Security and the Department of Defense, and research it does for private industry may be proprietary.

"Putting that at risk is just not acceptable," Harvey said.

There may be some loss of productivity as employees try to get some work done in between cybersecurity sessions today with limited software operating on the lab's computer network, but the inconvenience should help drive home the importance of tight cybersecurity, he said.

The stand-down was planned as a result of a DOE test of cybersecurity systems in May.

About 450 employees were sent an e-mail message that "looked very official," Harvey said. They earlier had been notified that they would need new training for security badges.

The phishing e-mail they then received as part of the cybersecurity audit directed them to go to an Internet site and follow directions that included clicking on a button that supposedly would change printing parameters for a training certificate.

Although the website appeared to be an official DOE site, it actually was an impostor site that ended with the suffix ".net" rather than the ".gov" used by DOE. Employees who clicked on the button allowed the DOE audit team broad access to the lab's unclassified computer network.

About 10 percent of those who received the fake e-mail fell for the ruse, said Staci West, lab spokeswoman.

However, because it was only a test, there was no breach of security or loss of personal information.

"DOE believes that standing down the computer network for the day is the best way to highlight to PNNL staff the need to recognize, understand and respond appropriately to the ever increasing threats," Talbot said.