O-Toluidine is a synthetic chemical used in dye manufacturing. It contaminates water through industrial discharge and is classified as a carcinogen linked to bladder cancer.

O-Toluidine is widely used in rubber, pesticide, and pharmaceutical production. It enters water systems primarily through industrial wastewater discharge. Environmental agencies typically detect o-toluidine using gas chromatography-mass spectrometry. While regulated as a hazardous substance, specific drinking water standards are not universally established. Due to its carcinogenic potential, minimizing exposure is recommended. Water treatment methods like activated carbon filtration can help reduce o-toluidine levels in contaminated water supplies.