No one expects an emergency or disaster to occur. Some Pre-planing will make a major difference. Reasonable steps include training of employees, supervisors and labor alike on what thier role is in an emergency situation. The results will be mitigation of the negative impacts of an emergency or disaster. Emergency Crisis plans outline escape procedures, escape routes, emergency shut down procedures, the use of fire extinguishers, SCBA equipment and a command chain of who handles press inquiries.
When the fertilizer hits the ever present fan everyone on site will know what to do. This increased understanding will greatly decrease confusion and chaos at a time when deliberate actions are most needed.
Check out the OSHA FactSheet on work place emergencies at Doc/data_General_Facts/factsheet-workplaceevergencies.pdf and 29 CFR 1910.38.