Abstract: A composition comprising tris(hydroxymethyl)phosphine or phosphorus-containing salts or condensates of those salts with nitrogen-containing compounds coated or absorbed onto a solid or porous substrate is disclosed. The salts or condensates are based on tetrakis(hydroxymethyl)phosphonium salts. The substrate has a melting point greater than 70° C. and is an optionally hydroxyl-substituted di- or polycarboxylic acid. The compositions may be used with water soluble film forming polymers to make sachets or bags containing sachets or bags of these phosphorous-containing compositions along with sachets or bags of compositions that are incompatible with these phosphorous-containing compositions.