2-methyl 1,3-propandiol (MPD) is a low molecular weight, colorless glycol used in polymer and coating applications. The log Kow of −0.6 suggests partitioning to aqueous phases with a low concern for possible bioaccumulation. MPD was found to be inherently biodegradable. Ecotoxicological results in several aquatic and terrestrial species found no significant hazard potential. MPD is rapidly absorbed via the oral and dermal routes, metabolized to 3-hydroxybutyrate, and excreted in urine with a half-life of 3.6 h. Acute toxicity testing found low toxicity via all routes. Barely perceptible skin irritation was observed in human volunteers, whereas there was no evidence of irritation in rabbits. Skin sensitization in Guinea pigs was negative. Human skin patch results indicated minimal response in about 1% of individuals. There was no evidence of mutagenicity using bacterial and mammalian test systems. A 90-day oral study in rats found no adverse effects at any dose. Three developmental toxicity studies in rats and rabbits, found no treatment-related maternal toxicity, fetal toxicity or malformations. A two-generation reproduction study in rats found no consistent treatment-related adverse effects on reproduction in either generation. No carcinogenicity studies with MPD were identified. MPD presents a low degree of toxicological and ecotoxicological or environmental hazard.