rollins edwards still has thick scrabz that he scratches until they bleeds.fect the airways so you can get copd, asthma. all kinds of very serious and sometimes life threatening illnesses. >> woodruff: he's well into his 90's right. >> that's true. the veterans i was able to talk to for these stories are of course an exceptional group having far outlived their life expectancy and having gone through this. we can assume there are many more who aren't around to tell us their stories today. >> woodruff: professor smith why was the government doing this? what were they trying to find out? >> well, the first world war had been a chemical war and there was every expectation that this second world war would be one as well. so the allied governments, canada, the united states, great britain, australia, all prepared for a chemical war. this is also al true of the japanese and nazis. so chemical was everyone's expectation and the scientists were involved in helping with that research. >> woodruff: but why did they choose a number of african american men japanese americ