In fact, the initial evidence in other countries that a major release of radioactive material had occurred came not from Soviet sources, but from Sweden, where on 28 April workers at the Forsmark Nuclear Power Plant (approximately 1100 km from the Chernobyl site) were found to have radioactive particles on their clothing.
As primeiras evidencias de que unha liberación de gran cantidade de material reactivo estaba afectando a outros países non chegaron de fontes soviéticas, senón de Suecia, onde na mañá do 28 de abril os traballadores da central nuclear de Forsmark (a uns 1 100 km de Chernóbil) atoparon partículas radioactivas na súa roupa.