To meet the UL 1203 requirements, samples of EP41S-6 were exposed to saturated vapors in air for the following chemicals: acetic acid (glacial), acetone, ammonium hydroxide (20% by weight), ASTM reference fuel C, diethyl ether, ethyl acetate, ethylene dichloride, furfural, n-hexane, methyl ethyl ketone, methanol, 2-nitropropane, and toluene. After 168 hours of exposure to these vapors, sample castings in groups of 6 were observed for discoloration, swelling, shrinking, crazing, cracking, leaching, and dissolving. The samples were also subjected to a crush test before and after exposure to these chemicals. The crushing force for EP41S-6 was not less than 85% of the original value. EP41S-6 has successfully met or exceeded the requirements of these tests.