154.1830—Warning sign.
        
        (a) 
         The master shall ensure that a vessel transferring cargo, while fast to a dock or while at anchor in port, displays a warning sign:
    
    
    
    
        
        (b) 
         Except as provided in paragraph (e) of this section, each warning sign must have the following words:
    
    
    
    
    
    
    
    
    
    
    
        
        (4) 
         Be 5.1 cm (2 in.) wide, except for “M” and “W” which must be 7.6 cm (3 in.) wide, and the letter “I” which may be 1.3 cm ( 1/2 in.) wide; and
    
    
    
    
    
    
    
    
        
        (e) 
         The words “No Smoking” and “No Open Lights” may be omitted when the cargoes on board a vessel are not flammable.
    
    
        
        (f) 
         When a vessel carries or transfers vinyl chloride, the warning sign under paragraph (b) of this section must also have the words “Cancer Suspect Agent.”