An IC must rapidly transition from a Type 5 single-engine response to a multi-agency Type 3 event after a large anhydrous ammonia release. Which action is MOST consistent with NFPA 470 Ch. 12?

1. Maintain the same single-IC structure indefinitely
2. Expand the organization, activate command/general staff as needed, and request a written IAP for the next operational period
3. Disband the initial command structure and start over
4. Refer command to the local emergency manager only