Unless a situation is expressly deemed in statute to meet the emergency standard, an agency must make a finding of emergency by describing specific facts supported by substantial evidence that demonstrate the existence of an emergency and the need for immediate adoption of the proposed regulation. In addition, if the emergency existed and was known by the agency in sufficient time to have been addressed through nonemergency regulations, the finding of emergency shall include facts explaining the failure to address the situation through nonemergency regulations. A finding of emergency based only upon expediency, convenience, best interest, general public need, or speculation, is not adequate to demonstrate the existence of an emergency. (Government Code section 11346.1(b)(2).)