dr. john howard with the national institute for occupational safety and health. we are talking about public health and the gulf of mexico oil spill. john: one of my biggest concerns about the whole situation, not exactly on topic but really important to address for the futu future, i have read that there is an acoustic switch that could have been used that would have cut the leak off below the source or below the ground, and the companies involved decided that it was too expensive to put it and from what i understand they cost about a half million dollars. chris: tyler, again, we are talking about public health with the the gulf oil spill. i don't think dr. howard -- guest: that is a little outside my field of expertise. chris: craig, lake charles, louisiana. democrat. you are on, please go ahead. john: good morning. just had a question about the dispersant how it was banned in other countries and they brought it here to use on our gulf coast which we depend on our seafood and oil and gas for servicing the rest of the country. second of all, why did they need to u