An update to this story is posted here.

SPRINGFIELD — First responders are on the scene in East Springfield after a series of apparent explosions early Saturday morning.

Although it is unclear what caused the incident, several police and fire crews established a perimeter amid heavy smoke and several houses near the site have been evacuated.

The still unknown incident appears to be close to the site of the old Jahn Foundry, which sustained a serious explosion back in 1999 when three workers were killed and nine others were seriously injured.

That site was also the scene of another incident in 2006 when a fire inside a warehouse holding aluminum and magnesium, now part of the Joseph Freedman Metal Recycling company, was doused by firefighters.

The Republican has a team on the scene and will publish additional information on MassLive.com as it becomes available.

The map below shows the approximate location of the incident.