By Martha Groves, Los Angeles Times, 5/30/2014.
The rat poisons that Reckitt Benckiser Group has agreed to discontinue contain "second-generation anticoagulant rodenticides." These are more toxic and persistent than the previous generation of products. The poisons are designed to kill rodents by thinning the blood and preventing clotting.
Scientists say the products have for years wreaked havoc by working their way up the food chain [when poisoned rodents are consumed by scavengers and predators, which are then, in turn, poisoned and often killed].
Some activists credited California's action with inducing the company to give in. In March, the California Department of Pesticide Regulation signaled plans to halt retail sales of second-generation rat poisons to consumers after July 1. The manufacturer opposed the ban.
This is a step in the right direction, but of course, it doesn't solve the problem of secondary poisoning.