I was always taught blue for kerosene, red for gas, and yellow for diesel
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2.2 Color
Portable fuel containers shall be color coded for specific fuels:
a) Gasoline – red;
b) Diesel – yellow; and
c) Kerosene – blue.
Each portable fuel container must have identification markings on the
container and on the spill-proof spout.
a) Red containers shall be permanently identified with the embossed
language, or permanent durable label “GASOLINE” in minimum 34-point
Arial font or a font of equivalent proportions.
b) Yellow containers shall be permanently identified with the embossed
language, or permanent durable label “DIESEL” in minimum 34-point
Arial font or a font of equivalent proportions.
c) Blue containers shall be permanently identified with the embossed
language, or permanent durable label “KEROSENE” in minimum 34-point
Arial font or a font of equivalent proportions.
http://www.arb.ca.gov/regact/pfc/2005/cp501.pdf