Decontamination of a radioactive spill should occur __________.

The correct process for decontaminating a radioactive spill is to start from the least contaminated areas and move towards the most contaminated areas. This approach helps to prevent the spread of radioactive materials during the decontamination process. By addressing the least contaminated regions first, responders can minimize the risk of contamination spreading to those areas that are not as severely affected.

This method is critical in maintaining safety and ensuring an effective response to a spill. It helps to control contamination and allows responders to manage and contain the radiological hazards more efficiently.

The other approaches would not effectively prevent the spread of contamination. Starting with the most contaminated areas could inadvertently release more radioactive material into less affected regions, worsening the situation. Waiting for the radioactive isotope to decay before beginning decontamination could pose significant risks, as immediate hazards may still exist. Additionally, prioritizing life-saving techniques is essential, but decontamination should be timely, especially if the spill poses a risk to first responders or others.