I have heard that you need to have a special chemical license to posses and handle the phosphate part???
Yes as a shop owner and as a plating facility you have to have the epa requirements met to purchase Manganese phosephate or Zinc phosephate, in their raw and pure form, they are both Heavy Metals and you need proper training to handle them correctly... phosephate burns aren't pretty... they hurt like hell another solution is to parkerize and the zinc, or manganses contant isn't that high as with true phosephate