Over half a billion eggs have now been recalled so far in the United States since the recent salmonella outbreak. On Friday the ban was extended to include another Iowa farm. Environmentalists are saying that factory conditions are to blame. The salmonella outbreak has made more than 1,000 people sick and the number of people sickened will only be increasing.

After laboratory tests confirmed the eggs were tainted with salmonella, Iowa’s Hillandale Farms said that it would be recalling more than 170 million eggs. The latest recall puts the total number of potentially tainted eggs at about 550 million.