An accidental release of anhydrous ammonia occurred, as defined by Section 112(r)(2)(A) of the CAA, 42 USC 7412(r)(2)(A). Respondent failed to prepare a sufficiently detailed SOP to correctly isolate the safety relief valves utilizing a 3-way manifold as required by 40 CFR 68.69(a)(l)(iii), Temporary Operations (valve changes). 40 CFR 68.69(b) requires that written Operating Procedures should be readily accessible to employees who work in or maintain a process. Respondent failed to establish procedures and train employees to safely isolate the pressure relief valves in violation of 40 CFR 68.71(a) and (b), Initial and Refresher training.