Aurora Cooperative - South NH3 Plant - Executive Summary

| Accident History | Chemicals | Emergency Response | Registration | Source | Executive Summary |

The Aurora Cooperative Elevator Company's accidental release prevention policy involves a unified approach that integrates technologies, procedures, and management practices.  The Aurora Cooperative emergency response plan involves the response services available in the community.  Aurora Cooperative bulk Anhydrous Ammonia facilities have been strategically located to provide a local retail facility for this form of affordable nitrogen fertilizer for agriculture.  This location at 315 8th street in Aurora is made up of two (2) 30,000 gallon pressurized storage vessels and four loadout risers.  It serves the Central Hamilton County area.  This facility is normally unmanned, except during the fertilizer season, although the adjacent grain elevator and office facilities are normally manned during business hours.  The offsite consequence analysis includes consideration of two anhydrous ammonia release scenarios, identified as "worst case release" and "alternative scenario".  The first Scen 
ario is defined by EPA, which states that the "owner or operator shall assume that the...maximum  quantity of the largest vessel...is released as a gas over a 10 minute period", due to an unspecified failure.  The alternative release scenario is defined as "more likely to occur than the worst case scenario".  Atmospheric dispersion modeling has to be performed to determine the distance traveled by the anhydrous ammonia released before it's concentration decreases to a "non-toxic" level.  For this purpose, Aurora Cooperative has chosen to use RMP-Comp version 1.05 to determine the distance to the toxic endpoint (.14mg/l or 200 ppm) and to determine the population affected by a potential release by using maps extracted from Landview III software.  The worst case release scenario for the Aurora Cooperative - South anhydrous ammonia facility in Aurora involves failure of one of the two 30,000 gallon pressurized storage vessels while it contains 85% (maximum allowed capacity) of it's capaci 
ty.  The alternative release scenario is based on the failure of  a three inch transfer hose, assuming the check valve fails completely and the excess flow valve in the storage vessel takes two minutes to close.
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