Lindbergh Boulevard was closed between West Watson and East Watson in Sunset Hills for more than 12 hours starting late Thursday night due to concerns about a possible explosion at a storm-damaged medical center. The road was reopened around 11 am Friday after stored helium at the SSM Imaging Center was safely vented. (KMOX/Brett Blume)

SUNSET HILLS, Mo. (KMOX) -  Lindbergh Boulevard between West Watson and East Watson in Sunset Hills was reopened for traffic shortly after 11 am Friday.

It had been closed for more than twelve hours after officials determined late Thursday that there was a less than 1% chance of an explosion at the storm-damaged SSM Imaging Center, with a potential blast radius of 100-meters (330-feet) in any direction.

That meant several homeowners who had found themselves in the path of the New Year’s Eve storm had to evacuate their homes.

The problem centered on the venting of helium from an MRI scanner at the now-closed SSM Imaging Center.

Helium in its liquid state is stable and inert, but the storm knocked out electricity to the building and thus the refrigeration units for the helium.

There was a concern that as the stored helium warmed up and began converting to a gaseous state, it would expand and increase pressure on the storage tanks, possibly resulting in an explosion.

After determining that there was indeed damage to a ventilation pipe atop the building, technicians worked to correct the problem and then conducted a successful test venting of the stored helium.

It was then determined that the danger of an explosion had passed and Lindbergh was reopened to traffic.

(Copyright KMOX Radio)