A facility used for the discharge of a cargo of a particular hazard，such as chlorine，butane or ethane，must have what to warn water traffic of an immediate danger during fire or cargo release?（）

An emergency boat and crew
B. A siren or rotating flashing light
C. Flashing red lights located one-half mile upstream and downstream of the facility
D. Buoys with flashing lights controlled from shore，located one-half mile upstream anddownstream of the facility