Dimethyl sulfate is a colorless, oily liquid that is primarily used as a methylating agent in chemical reactions. It is known for its ability to introduce methyl groups into various organic compounds, making it valuable in the production of pharmaceuticals, pesticides, and dyes. However, it is highly toxic and can cause severe health issues upon exposure. Due to its hazardous nature, dimethyl sulfate is classified as a dangerous substance and requires careful handling. It can cause serious burns and respiratory problems, and even small amounts can be lethal. Safety precautions are essential when working with this chemical in laboratory or industrial settings.