California Code, Public Resources Code - PRC § 42849

(a) “Threaten” or “threat,” for purposes of this article, means a condition creating a substantial probability of harm, when the probability and potential extent of harm make it reasonably necessary to take immediate action to prevent, reduce, or mitigate damages to persons, property, natural resources, or the public health or safety.

(b) If the board finds either an imminent threat to public health, safety, or the environment, or a threat, as defined by subdivision (a), the board may conduct an emergency meeting to determine the legal, enforcement, cleanup, or other necessary actions that may be taken to correct that imminent threat or threat. Such a finding by the board shall be deemed to be an “emergency situation” for purposes of, and in addition to the situations described in, Section 11125.5 of the Government Code.