I think it was suggested in the seventies that it was not as effective, so the concentration of NTA in detergents initially--in the late seventies, if memory serves--was as much as 25% by weight. I don't know that it's still used now. I think there are a variety of other things--silicates and citric acid and things like that--that we used in its place because of the concerns that were raised at that time.
The point is that we need to know what the substitute would be before we know that we're moving in the right direction--whatever the substitute is in this case. I don't know what it is in this case.