No one expects an emergency or disaster to occur. But that is where Emergency Crisis Planning comes in. Pre planing and training of employees, supervisors and labor alike, can mitigate 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 preverbal fan, everyone on site understanding what they need do 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.