The events associated with the death of Gloria Ramirez at Riverside General Hospital on 19 February 1994 have been portrayed as a major medical mystery. A potential chemical explanation for this incident has been developed. The hypothetical scenario depends upon the oxidation of a common solvent, dimethyl sulfoxide, through dimethyl sulfone to dimethyl sulfate. The latter compound is a volatile and highly toxic agent that can be quite hazardous to humans in small amounts. It is also environmentally nonpersistent. Much of the mystery surrounding the circumstances at the hospital may be explainable if this postulated metabolic pathway took place at the time of the emergency room incident. Although dimethyl sulfate was not detected in any analyses pertinent to this event, there are plausible scientific explanations to account for that fact. The sulfate anion, a hydrolysis product of dimethyl sulfate, was measured at an appreciably elevated concentration in Ramirez' blood. The descriptions of the symptoms of the hospital-staff victims appear quite consistent with dimethyl sulfate exposures. This paper attempts to make some sense of the reported data and eyewitness accounts, and perhaps provide new insight for any future research that could further explain this reported occurrence of toxic exposure.