I'm watching Chernobyl on HBO and just wondering why the contaminated workers continued to pose a danger after being taken hundreds of miles away from the explosion site. The initial meltdown sent high energy radioactive elements into the immediate area that damaged their cells. However, once the workers were taken away from the initial site, did those high energy particles continue to bounce off them onto people in their immediate area or through physical contact?
You have three kinds of immediate radiation, alpha, beta and gamma radiation. Their penetrating power differs as well.
Most of the radioactive particles from that disaster are sufficiently well handled with barriers, protective clothes, respirators. Most important here thar humans do not ingest them via air, food or fluids.
But once they are inside the body, these elements continue to decay, sending out all three kinds of radiation. In effect the body is then the source of increased radiation. On a much smaller scale, those elements could also be excreted or shedded.
As was noticed after Fukushima as well:
By March 16, media reports of contaminated airline passengers from Japan arriving in China prompted international concerns about harmful levels of radioactive materials being carried by travelers leaving the country.
After the Chernobyl disaster, a 1986 British study of 45 air passengers from Eastern Europe used whole-body assessments and measurement of thyroid radioiodine and detected radiological contamination at 56 times the background level. Some American travelers returning from the Chernobyl site found their clothes and luggage were also contaminated.
The 2006 poisoning of a Russian ex-KGB officer in London led to detectable levels of radioactive polonium-210 in several locations visited by the victim and the suspected perpetrator. The British Health Protection Agency (HPA) notified US public health officials of 200 US residents who were at risk of contamination with polonium. State health departments contacted these travelers and advised them to contact a physician (Centers for Disease Control and Prevention [CDC] internal e-mail communication, 2011). In addition, British Airways (BA) identified and published a list of 221 flights involving potentially polonium-contaminated aircraft. BA advised nearly 33 000 travelers to contact HPA.
Todd Wilson et al.: "US Screening of International Travelers for Radioactive Contamination After the Japanese Nuclear Plant Disaster in March 2011", Disaster Medicine and Public Health Preparedness, Volume 6, Issue 3 October 2012 , pp. 291-296. DOI