EPA issues “letters” on their website that helps clarify many of their rule requirements, much like OSHA’s Letters of Interpretation. This week OSHA issued twenty-one (21) such letters following their FINAL amendments to their Risk Management Plan rule. These two (2) letters address what EPA has done to further the safe storage and handling of Ammonium Nitrate and explains why EPA didn’t revise the RMP list of regulated substances to include Ammonium Nitrate. Here is what EPA said: