In Holland again there was an explosion in a modern freestall barn with low ammonia exhaust. The barn had a so called semi closed floor with a manure pit underneath. Ammonia and methane from the manure can hardly emit which makes this type of barn environmental friendly according to official guidelines. When someone was welding in the barn there came a spark in the manure pit followed by an explosion. There was a high flame and the concrete floor was lifted and fell back.