Dimethyl sulfate vapor may cause injury to the eyes and adjacent tissues that varies from slight irritation with tears to severe inflammation and edema of the eyelids and the eyeball. Irritation of the eyes may not be noted until several hours after exposure to low concentrations of the vapor. After the acute effects have subsided in severe cases, increased sensitivity to light, partial color blindness, and reduced visual acuity may persist.
An early symptom of overexposure to dimethyl sulfate vapor is a fiery red inflammation of the eyes (possibly accompanied by a delayed burning sensation). If this occurs, first aid should be given promptly, and appropriate preventive action should be taken to ascertain presence of possible leaks. Because of variation in individual susceptibility and possible delayed effects, these symptoms should not be relied on in lieu of other methods of monitoring air concentrations of DMS.
Dimethyl sulfate vapor is extremely irritating to all parts of the respiratory tract. This irritation may not be noted until several hours after exposure. Mild exposure leads to dry, painful cough, chest pain, and irritation of the nose and throat that may pass in 1 or 2 days, leaving only dryness of the throat. Moderate exposure causes reddening and swelling of the nasal mucous membranes and the vocal cords. The lungs and trachea are affected; there may be foamy, white sputum. With proper treatment aimed at reducing cough, the patient may recover in a few days; otherwise, more serious injury to the lungs may follow. In 6 to 8 hours, severe exposures lead to great difficulty of breathing, with general malaise and fever as well as a rapidly developing inflammation and edema of the lungs. Severe exposures may be fatal.
Skin exposure to high concentrations of the vapor may produce reddening and possible burns. In exposure to high vapor concentrations, dimethyl sulfate may penetrate the skin and produce systemic poisoning.