We provide many utilities with Liquid Ammonium Sulfate. It is usually injected after CT to for chloramines rather carrying a free chlorine residual. This effectively stops the formation of DBP's. It is very safe, but monitoring is essential by checking total chlorine, monochloramine, and free ammonia routinely. We check for nitrates and nitrites in distribution. We also will periodically turn it off for a couple of weeks to "burn out" with chlorine if we see any nitration developing.