In this report are given the results of a study of the effects on aviation gasoline of storage in Duprene-Lined hose. The results show that such storage does not affect the octane rating but does increase the "gum" content of the gasoline. After repeated extractions, however, the amount of extraction products can be kept below 10 milligrams/100 c.c. provided that the storage contents of the hose are mixed with 10 or more gallons of gasoline which has not been stored in Duprene. The use of Duprene-lines connectors on the gasoline line from the tank to the carburetor may give a high "gum" content for the first 150 c.c. (6 oz.) of gasoline delivered to the engine. This Laboratory does not know if this is undesirable.