Enhanced levels of non-volatile nuclides: ^141,144Ce, ⁹⁵Zr, ⁹⁵Nb, ^103,106Ru, ^238,239,241Pu, ²⁴¹Am, ^242,243,244Cm and ^154,155Eu were observed in the samples from north-eastern Poland. This was considered to be a result of finding in sample a single „hot particle”. Investigations conducted in the Institute of Nuclear Physics allowed us to conclude that on this area a non typical isotopic composition of Chernobyl fallout was very common. The enhanced activities (up to 100% above the global fallout value) of ⁹⁰Sr, ^238,239,240Pu and ²⁴¹Am were observed. The presence of ^243,244Cm and ^154,155Eu was confirmed. It seems that the quasi-continuous fallout of huge numbers of small "hot particles” occurred there from the high altitude radioactive cloud, which moved toward the Scandinavia on 26th of April, 1986.