What effects may extreme radiation such as from a nuclear accident have on a single individual?

Extreme radiation exposure from a nuclear accident can lead to acute radiation syndrome (ARS), which manifests through symptoms like nausea, vomiting, and fatigue, often occurring within hours. It can damage the bone marrow, leading to decreased blood cell production, increasing the risk of infections and bleeding. Long-term effects may include an elevated risk of cancer and other health complications due to cellular damage. Psychological effects such as anxiety and trauma may also arise from the experience of the accident itself.