nitarsone nitarsone nitarsone is an organoarsenic compound that is used in poultry production as a feed additive to increase weight gain, improve feed efficiency, and prevent histomoniasis (blackhead disease). it is marketed as histostat by zoetis. nitarsone names preferred iupac name (4-nitrophenyl)arsonic acid other names (p-nitrophenyl)arsonic acid; 4-nitrobenzenearsonic acid identifiers cas number 98-72-6 y 3d model (jsmol) interactive image chemspider 60190 echa infocard 100.002.451 pubchem cid 66826 unii jp2en8woru y comptox dashboard (epa) dtxsid9045007 inchi inchi=1s/c6h6asno5/c9-7(10,11)5-1-3-6(4-2-5)8(12)13/h1-4h,(h2,9,10,11)key: fuufqlxaiuowml-uhfffaoysa-ninchi=1/c6h6asno5/c9-7(10,11)5-1-3-6(4-2-5)8(12)13/h1-4h,(h2,9,10,11)key: fuufqlxaiuowml-uhfffaoyaa smiles o=()c1ccc(cc1)(=o)(o)o properties chemical formula c6h6asno5 molar mass 247.038 g·mol−1 melting point 298–300 °c (568–572 °f; 571–573 k) (decomposes) except where otherwise noted, data are given for materials in their standard state (at 25 °c , 100 kpa). infobox references nitarsone once was one of four arsenical food-animal drugs—along with roxarsone, arsanilic acid, and carbarsone—approved by the u.s. food and drug administration for use in feeding poultry. however, following the suspension of sales of roxarsone in the united states in 2011, nitarsone was thought to be the only arsenical animal drug actually marketed in the u.s. in september 2013, the fda announced that zoetis and fleming laboratories agreed to voluntarily withdraw from using roxarsone, arsanilic acid, and carbarsone, which left nitarsone as the only arsenical approved in the u.s. for use in food animals. but in 2015, the fda also withdrew approval of nitarsone in animal feeds, effective at the end of 2015.