Application Site: Feed through for poultry - caged layers only. The active ingredient is passed through the chicken, leaving a residue in the manure that controls the growth of the fly larvae developing there. Cyromazine is practically nontoxic (acutely) to mammals and birds. Exposure estimates for these organisms are <0.05 ppm. Acute toxicity for birds is 1785 ppm maximum. Safety factor is 105-106 for birds. Acute toxicity for mammals is 1000 ppm maximum. Safety factor is again 105 - 106. A summary of the environmental chemistry factors to be considered in this hazard assessment indicates that: - Cyromazine is stable to hydrolysis; photolysis is the dominant physico-chemical degradation mechanism. - Cyromazine is not expected to build up in soils; at 5 ppm in chicken manure (5 tons/A) <0.05 ppm cyromazine is expected in soils. Half lives in soil-manure are 1 year (lab) and 12 weeks (field/greenhouse). - Cyromazine is not expected to build up in plants or crops; <0.05 ppm is expected from typical chicken manure applications. - Cyromazine is not expected to build up in animal tissues; fish bioconcentration factors are expected to be between 0.2-7.8X. - Cyromazine has no detrimental effects on soil microorganisms. - Cyromazine has a low to moderate mobility in sandy or loam sand soils.