Look at it this way: a respirator is not cheap, but it is way, way, waaaaay cheaper than a new set of lungs and/or a new set of corneas. Wear safety goggles, too. Why not protect yourself? Are you not worth it? Yes of course you are! Take care of your health.

Polysul is lime-sulpher. Be careful not to spray when it is too warm, because you can burn the foliage. Follow all package directions. Water very well the day before so that the rose foliage is fully hydrated.

Polysul is a commercial brand of lime/sulfur (calcium polysulfide). Lime/sulfur is widely used as a dormant spray for roses . A much lower concentration has to be sprayed during the growing season and my impression is that very,very few people use it for this purpose, probably out of concern for leaf damage. It is made by mixing calcium hydroxide with elemental sulfur and because an excess of calcium hydroxide is used, it has a high pH (around 11) and high pH makes any substance dangerous to the eyes. Check the enclosed link for the EPA's summary of calcium polysulfide. Note that the EPA recommendations for handlers (page 6) includes protective clothing and goggles but only standard dusk/mist masks.

If I needed an organic-certified spray for rose powdery mildew, I would probably choose from elemental sulfur, horticultural oil, canola oil or potassium bicarbonate (GreenCure).

Here is a link that might be useful: Calcium Polysulfide, EPA

Thanks for the information on greencure. I am going to order it this week. I chickened out and did not spray the polysul. I went organic with a dishwashing liquid, vinegar, baking soda, and cooking oil solution. I hope it works.