NFPA 704
100

The color BLUE represent this.  

What is Health? 

200

The color RED represents this.  

What is Fire Hazard? 

300

NOT 6...7... the rating for NFPA 704 only goes this high. 

What is 4.  

400

Don't use this, notated by a capital "W" with a slash through it.  

What is water? 

500

Special Hazards are noted in this color box. 

What is white?  

M
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n
u