Final answer:
A decontamination plan should be created before any operations with hazardous substances start, ensuring safety and emergency preparedness.
Step-by-step explanation:
A decontamination plan should be developed before any operations begin with any hazardous substances. The correct answer to this question is c) before. This approach is part of standard safety protocols to ensure that all potential risks have been assessed and appropriate measures are put in place to safeguard the health and well-being of workers and responders. It is essential to have a clear plan outlining how to reduce or eliminate contamination from hazardous substances, including steps for emergency response, procedures for handling and disposal, and personal protective equipment requirements.