From @IAFF36:

“Gas Leak – 1200blk U St NW – gas line broken on sidewalk, evacuating multiple buildings, U St closed, gas co. requested #dcfd #dctraffic”

and

“Update – 1200blk U St NW – underground gas leak, FFs evac bldgs & monitoring w/ gas meters, HazMat req; 1200blk U St closed #dctraffic #dcfd”