The results of studies of the lead and silver content in water bodies and air and the ice nuclei concentrations in the regions subjected to hail protection in the Republic of Moldova in 19771991 are summarized. Until 1983, hail-hazardous clouds were seeded mostly with crystallizing pyrotechnic compositions based on lead iodide; subsequently, silver iodide was used. The problems of environmental pollution in the regions involved in the activities using various crystallizing reagents based on heavy metals are discussed. Accumulation of these metals depending on the type and lifetime of the reagents used is estimated.