Gardaí say they are treating this morning's security alert at the Intel plant in Leixlip, Co Kildare, "very seriously".
The alarm was raised shortly after 6am when gardaí received what they believe to be a credible threat.
The site was evacuated and a search was carried out by Intel personnel, with buildings declared safe just after 8.30am.
Employees then returned to work at the plant and activity has returned to the normal.
The company said most staff would not have arrived for work when the alert began, but there would have been a number of shift workers on site.
Gardaí remain at the scene and are investigating the circumstances leading to the alert being issued.