According to our news partner, The Seattle Times:
The Seattle Fire Department has shut down Westlake Avenue North at Highland Drive because of liquid leaking from two barrels labeled “danger.”
News helicopters are covering the scene, part of Westlake Ave N is closed.
UPDATE: Per SFD, “the Haz Mat team has determined the contents of two 55 gallon barrels is non-hazardous. The lot will be locked up and Westlake Ave will reopen.”