Ethylamine, benzylhydrazine, and low molecular weight fatty acids such as acetic acid, propionic acid, isobutyric acid, butyric acid, isovaleric acid, and valeric acid were discovered in most of the samples. It is believed that incomplete degradation during storage and thermal degradation during the processing of nonrubber components (carbohydrates, proteins, and lipids) are responsible for generating the offensive odor.