Pig barn workers are exposed to dust, gases, and endotoxins. In a study, it was found that dust exposure varied little between different areas of the barn. However, there is a large difference between areas (farrowing, nursery, grow-finish) when dust particles are larger than 5.0 microns. Results were inconclusive for ammonia measurements. 10% of workers in different areas of the barn are exposed to the 20-ppm limit of H2S regularly. Endotoxins (by-products from bacteria) vary quite a bit between farrowing, nursery, and grow-finish (nursery and grow-finish being the most). This could be due to a higher relative humidity in the nursery/grow-finish area.