Black fiberglass tissue is generally safe to use when proper precautions are taken. It is made from the same material as regular fiberglass, which is widely used in various industries. However, it's important to note that inhaling fiberglass fibers can be harmful to health, so it's crucial to use personal protective equipment (PPE) such as masks and gloves when handling it. Additionally, it should be disposed of properly to prevent environmental contamination. Always follow the manufacturer's guidelines and safety regulations when using black fiberglass tissue.