There was a large fire at 118 Acacia Lane in Sterling. Prospect Waterproofing Company
As soon as it was dispatched there was already a large dark column of smoke visible throughout the county.
It was 2 alarms and brought under control quickly. Units from MWAA and Fairfax assisted. They're now in the phase of securing utilities (Washington Gas slow to arrive as usual), and there is a gas leak fire they're having to deal with, and a collapsed roof on top of some rack system making it hard to reach some lingering areas.
Two news helos are now over the area.