The human remains and other materials found in crypts can be highly contaminated with microorganisms. Archaeologists are exposed to microorganisms in many ways (e.g by inhaling dust, contaminating scratches or cuts). We aimed
at evaluating microbial hazards associated with human remains and bioaerosols formed during archaeological works
in burial crypts. The samples of the human remains, bioaerosols and personal protective equipment (dust respirators,
disposable coveralls) were collected during archaeological works in the vault of the Cathedral Basilica of St. John the
Baptist and the Assumption of the Blessed Virgin Mary in Przemyśl (Fredro crypt). The microbiological examination
involved determining the number of spores of aerobic and anaerobic bacteria, the number of mesophilic and hemolytic
bacteria, and the number of xerophilic, non- xerophilic and keratinolytic fungi. The air as well as objects and materials found in crypts are highly contaminated with bacteria and fungi. The xerophilic fungi were the most numerous in
all samples of human remains 1–230·103 cfu(colony forming units/g). The non-xerophilic fungi were predominant in
bioaerosols (>104 cfu/m3 during archaeological works). The majority of bacterial strains (81.3%) belonged to the genus
Bacillus. Fungi belonging to the genera Penicillium (65.2%) and Aspergillus (28.6%) dominated among the isolated
fungi. Fogging sterilization of the crypt turned out to be ineffective. The high number of microorganisms both in the
air and on human remains indicates that there is a need for particular caution during archaeological works which
cause dust emission. In order to reduce exposure to harmful biological factors, the use of disposable personal protective
equipment seems necessary
