The measurements and analysis of the ambient conditions in a building that on deep-litter show important risks to the human health. The highest concentration of total and Gram-negative bacteria were found during the winter period and those concentrations were 27 and 4 times (respectively) higher than the limits recommended in waste treatment and composting facilities. The highest concentration have been measured after the litter is being stir (weekly necessary maintenance procedure for the deep-litter). Exposition to the high level of those contaminants by the farmer or stock person can result in respiratory problems.