Which action related to cremation is prohibited without express written approval?

Cremating more than one body simultaneously is prohibited without express written approval because it raises significant ethical, legal, and health concerns. Regulations are designed to protect the dignity of the deceased, ensure proper handling and identification, and provide for the individual wishes of families regarding the cremation process. Each body requires specific attention and processing, and combining multiple bodies can lead to potential mix-ups, loss of identifying information, and emotional distress for families. This prohibition ensures that each cremation is performed with the respect and care that is owed to every individual, safeguarding against any mishaps that may arise from cremations being conducted simultaneously.

Other actions, while they may have regulations surrounding them, are not specifically identified within the laws as requiring the same level of express written approval. The framework for cremation practices is focused on individual dignity and identification, which is why this particular action is emphasized as needing clear, documented consent.