What type of material should clothing not be made from when working with machines that produce sparks?

When working with machines that produce sparks, clothing made from synthetic materials, such as nylon, is not advisable because these fabrics can melt when exposed to high temperatures and sparks. This melting can lead to severe burns and injury, as the molten material can adhere to the skin. In contrast, natural fibers like cotton and other materials typically have a higher ignition point and are less likely to melt.

Choosing clothing made from materials designed for safety, such as flame-resistant fabrics, is crucial in environments where sparks are present. Selecting the right type of clothing not only helps in preventing burns but also minimizes the risk of static electricity buildup, which could ignite flammable substances. Therefore, wearing clothing made from synthetic fibers in a high-risk environment is not safe.