A MAJOR incident is unfolding at Prescot Road, St Helens this afternoon.
A large police presence is at the site and a huge section of surrounding roads have been sealed off.
Sources have told the Star the incident centres on Alfred H Knight International Ltd, a business with global interests, that analyses metals and minerals.
Police have issued a brief statement saying they are dealing with a security alert.
The incident is said to be ongoing, say police.
A Merseyside Police spokesman said: "We are dealing with a security alert at a business premises in West Park, St Helens.
"We were called at 11.30am following reports of a man acting suspiciously. The business premises have been evacuated while checks are carried out."
"Prescot Road and Freckleton Road are closed and Prescot Road with the junction of Lugsmore Lane, Thatto Heath are closed." Motorists are being advised to avoid the area.
Alfred H Knight is based on Eccleston Grange, Prescot Road.
The company carries out work across America, Southern Africa, Asia and Europe.
Callers to the the Star's newsroom say some homes and businesses nearby were evacuated.
Students at the nearby Carmel College were kept on site since this morning, but they are expected to be sent home this afternoon.
A heavy police presence and at least a dozen fire crews have also been stationed at the scene throughout the day.
A large media contingent has been gathering throughout the day.
A further police statement is expected later this afternoon.