Hopefully you will never find yourself in an emergency situation but if you do it's important to remember the below steps. 

Immediate Safety

Your first goal is to ensure the safety and security of everyone in the workplace. Depending on the nature of the situation there may or may not be any injuries. 

Prevent Further Exposure - Most of the situations you could face will involve an accidental exposure, like spilling a chemical on exposed skin. It's important that before you take any action you remove the danger and prevent anyone else from being exposure.  For example you do not want to exposure yourself to a dangerous chemical while providing first aid to someone else. 

Provide First Aid and if necessary, direct another employee to call 911 - If you are first aid qualified and it is safe to do so you may begin providing first aid.  Depending on the level of injury it may be necessary to call 911. If possible direct a specific person to do so. 

Notify Manager / Supervisor - Once the immediate danger has subsided you must notify your manager or supervisor so that they can engage any emergency protocols.  It's essential that they are aware of any incidents so that they can properly report them and investigate to prevent further issues. 

Further Information

You may face an emergency situation where you do not know how to respond. While it is important to very quickly assist, you do not want to place yourself at risk. 

Examine the Label for more information - If you are unfamiliar with the hazardous material the label will be your first source of information.  Using your WHMIS understanding it should give you an idea of the risks and precautions that need to be taken.  It's possible that this information may not be enough.  

Read the SDS (First Aid Measures / Accidental Release Information) - If the label does not provide you with sufficient information you may need to consult the SDS.  The First Aid Measures will tell you how to treat an incident and the accidental release information will tell you how to manage the site of the incident. 

Follow-Up

Hospital Visits - Should the incident be serious enough that someone needs to be taken to hospital it is important that they take a copy of the SDS sheet for the chemical that they were exposed to.  This is key in allowing the hospital staff to provide the correct treatment. 

After Incident Reporting - Once the incident has been managed it is important that an investigation take place.  This will be conducted by your manager however you will need to provide them with as much information as possible. 

The safety of everyone in the workplace is the primary concern in any emergency situation