Acute toxicity and chronic toxicity are dose-related. Skin exposure to ready-to-use concentrated glyphosate formulations can cause irritation, and photocontact dermatitis has been occasionally reported. These effects are probably due to the preservative benzisothiazolin-3-one. Severe skin burns are very rare. Inhalation is a minor route of exposure, but spray mist may cause oral or nasal discomfort, an unpleasant taste in the mouth, or tingling and irritation in the throat. Eye exposure may lead to mild conjunctivitis. Superficial corneal injury is possible if irrigation is delayed or inadequate. Death has been reported after deliberate overdose. Ingestion of Roundup ranging from 85 to 200 ml (of 41% solution) has resulted in death within hours of ingestion, although it has also been ingested in quantities as large as 500 ml with only mild or moderate symptoms. Adult consumption of more than 85 ml of concentrated product can lead to corrosive esophageal burns and kidney or liver damage. More severe cases cause "respiratory distress, impaired consciousness, pulmonary edema, infiltration on chest X-ray, shock, arrhythmias, renal failure requiring haemodialysis, metabolic acidosis, and hyperkalaemia" and death is often preceded by bradycardia and ventricular arrhythmias. While the surfactants in formulations generally do not increase the toxicity of glyphosate itself, it is likely that they contribute to its acute toxicity.