I found this story here:Among the ships sunk when German JU-88 bombers attacked the port of Bari on the night of 2 December 1943 was John Harvey, which was carrying mustard gas intended for use in retaliation by the Allies if German forces initiated gas warfare. Most of the released gas was carried out to sea by an offshore breeze, but many military and civilian personnel were temporarily incapacitated or killed by undetermined amounts of the gas which were held in solution in oil that was floating on the water. Of the more than 800 casualties hospitalized after the raid, 628 suffered from mustard gas exposure. Sixty-nine deaths were attributed in whole or in part to this cause.
Medical officers and aidmen treating the casualties were unaware of the presence of the gas, which was diluted sufficiently to be detected by odor. In the belief that casualties covered with oil but showing no physical damage were suffering from exposure and immersion, they were wrapped in blankets, still in their oil-soaked clothing, given hot tea, and left as they were for twelve to twenty-four hours while the more urgent blast injuries and surgical cases were treated.
Those with the energy and will to clean the oil from their own bodies suffered no serious damage, but the remainder suffered varying degrees of mustard burns. Eyes began to burn about 6 hours after exposure, and were so badly swollen in 24 hours that many of the patients thought themselves blind. The first deaths occurred without warning 18 hours after exposure.
About 90 percent of the gas casualties were American, the bulk of them merchant seamen. Since no U.S. hospital facilities were yet available in Bari - equipment for all but one of the U.S. hospitals scheduled for the area were destroyed in the bombing - casualties were hospitalized in British installations. [Adapted from: Wiltse, Charles Maurice. The Medical Department: Medical Service in the Mediterranean and Minor Theaters. (Washington: Office of the Chief of Military History, Dept. Of the Army): 350-351.]
http://www.history.navy.mil/faqs/faq104-4.htm