The office, washroom, feedroom and connecting hallway were constructed on top of a concrete covered manure storage that was located between two parallel swine barns. The tank was almost filled to capacity and due to be pumped out. The shower facility had not been actively used for several years and likely did not have any water in the drain trap, causing methane to escape into the office for some time. The spark ignited the methane gas that had accumulated in the office area causing an explosion and small fire. The farmer managed to escape from the office with second degree burns to his hands.
Ammonia is a colourless gas and has a characteristically pungent odour.
It is also lighter than air and can cause respiratory diseases in livestock when exposed to significant levels over an extended period of time. Ammonia irritates the eyes at levels in the range of 30 - 50 ppm. This gas tends to be a concern mainly in swine and poultry buildings. As a rule, if eye irritation occurs, the ventilation in the barn should be improved. It is in part the product of respiration and is found naturally in the atmosphere.