When are Alpha and Beta emitters considered hazardous?

Alpha and Beta emitters are considered hazardous particularly when they are ingested or inhaled because these routes allow the radioactive particles to enter the body directly. Once inside, they can cause significant biological damage, including cellular damage and increased risk of cancer due to their ionizing radiation.

Alpha particles, while they cannot penetrate the skin, can cause severe harm if they enter the body through ingestion or inhalation, as they have high mass and charge. Beta particles can also penetrate the skin but are more concerning when they are present in internal tissues. Therefore, the potential health impacts associated with internal exposure make ingestion or inhalation critical contexts for assessing the hazard of these radioactive materials.

Other options, like storage, exposure to sunlight, or transport, do not inherently involve the direct entry of these emitters into the body, which is why they are not viewed as the primary hazard in the same way as ingestion or inhalation.