Which of the following is a requirement for disinfectants used in a salon?

Disinfectants used in a salon must have a label with clear instructions. This is essential for ensuring that salon professionals can properly use the product according to the manufacturer's guidelines. Compliance with these instructions is critical for achieving effective disinfection, which helps to prevent the spread of infections and maintain a safe environment for both clients and staff.

Clear labeling provides instructions on dilution ratios, contact times, and safety precautions, which are crucial for the proper application of the disinfectant. This adherence to guidelines not only helps in meeting regulatory standards but also promotes effective cleaning practices, ultimately protecting public health in salon settings.

While other factors like cost and the ingredients used may influence a salon's purchasing decisions, the most crucial requirement focuses on effective use, which is explicitly communicated through clear labeling.