HOUSTON (AP) — Officials say efforts continue to drain a tank that is leaking flammable gas following a massive fire at a Houston-area petrochemical complex, prompting the closure of part of the Houston Ship Channel.

Intercontinental Terminals Company says pumping began Saturday afternoon to extract about 20,000 barrels of the pyrolysis gasoline, known as pygas, from the tank at the Deer Park facility. Vacuum trucks are removing liquid from a ditch.

A section of the Houston Ship Channel was closed Saturday after pygas leaked into the water. Coast Guard Petty Officer Kelly Parker says that remains closed Sunday and that the Guard hopes to reopen the waterway Monday morning.

Parker says 52 vessels are waiting to move, but the channel won’t reopen until air and water quality has improved.