CARGILL AgHorizions - Oxford, NE - Executive Summary

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The United States Environmental Protection Agency (USEPA) developed the Risk 
Management Program (RMP) rule (40 CFR 68) to assist facilities in preventing 
accidental releases of highly toxic or flammable chemicals.  The RMP established  
three levels of requirements for the program.  Programs 1 and 2 are for facilities that 
pose less risk to the environment and therefore have reduced compliance 
requirements.  Program 1 is designed for "no impact" facilities and has the fewest 
requirements, while Program 3 is the most stringent of the three levels. 
 
The program level for each facility is determined by: 
 
      Use of regulated substances in threshold quantity 
      Impact of an off-site public receptor (e.g., residence, school, park) 
      North American Industrial Classification System (NAICS) code 
      Five-year accident history 
      OHSA PSM (29 CFR 1910.119) applicability.  
 
This facility is regulated under Program 2 requirements under 40 CFR 68.1 
0 because: 
 
      It stores anhydrous ammonia in excess of the threshold quantity 
      A release from this facility could impact an offsite public receptor (residence) 
      It does not operate under a NAICS code specified in the rule 
      It is not subject to OSHA PSM (this is a retail facility). 
 
40 CFR Part 68 Subpart G applies to an owner or operator of a stationary 
source that has more than a threshold quantity of a regulated substance in a process, 
as determined under 40 CFR 68.115.  CARGILL stores more than the threshold quantity 
of anhydrous ammonia (10,000 pounds) for commercial sale as fertilizer.   Therefore, 
CARGILL is required to submit a Risk Management Plan (RMP) as defined in 
40 CFR 68.150 by June 20, 1999. 
 
The CARGILL AgHorizions is committed to operating in a safe and compliant manner.  
Employees involved in operating the ammonia storage and transfer facility are throughly trained 
to identify and understand the hazards posed by this the transfer proce 
ss.  Process safety and 
emergency response materials are kept on site and periodically reviewed.  Information includes 
information pertaining to the hazards of ammonia, process technology, process equipment, and 
emergency response procedures. 
 
The stationary source is the CARGILL AgHorizions anhydrous ammonia storage and transfer 
facility.  The facility has two stationary storage tanks with combined  capacity of 24,000 water 
gallons (112,000 pounds).  The facility also stores numerous smaller transportable tanks (nurse 
tanks) that are actually used in the fertilizer application process.          
 
The facility is required to complete one worst-case release scenario per 40 CFR 68.165(a)(2) to 
determine program applicability.  CARGILL has chosen to use the DEGADIS+ 
to determine offsite impacts. 
Worst-Case Scenario Parameters 
    1.   Land Use - Rural 
    2.   Release Qty - 112,000 lb  
    3.   Release Rate - 11,200 lb/min 
    4.   Release Duration - 10 min 
 
For this facility, a worst- 
case release would occur in the event that a primary ammonia tank 
would rupture and the entire contents would be released to the atmosphere in 10 minutes.  The 
worst-case scenario requires a ground-level release height (0 feet).  Release calculations are 
presented below: 
 
Sample Endpoint Calculation 
 
Given:         The Combined Tank Capacity is 24,000 water gallons 
                   ANSI K61.1 filling density = 56 % (of water wt.) 
 
Release Rate   = Tank Capacity / 10 minutes 
         = (24,000 gal * 8.345 lb/gal water)*(0.56)  / 10 min  
         = (200,280 lb)*(0.56) / 10 min 
         = 112,000 (rounded) / 10 min 
         = 11,200 lb/min 
 
Input of the preceding data into DEGADIS+ Comp program, the results indicate a worst-case 
impact of 2.1 miles for the facility.  The rule defines the toxic endpoint of anhydrous ammonia to 
be 0.14 mg/L.  The residential population within a 2.1 mile radius of the facility is 1,000 
(rounded) based 
on the 1990 US Census data.    
 
The facility is required to complete one alternate release scenario per 40 CFR Part 68.165(a)(2).  
The alternative release scenario considered is in accordance with the guidelines provided in 40 
CFR 68.22 and 68.28.  Alternative release parameters are presented below: 
Alternative Scenario Parameters                 
 
   1.   Land Use - Rural                  
   2.   Release Qty - 600 lb            
   3.   Release Rate - 60 lb/min  
   4.   Release Duration - 10 min 
 
The alternative scenario chosen for this facility involves a release because of a 
sudden split in the hose during transfer.  While this scenario is still unlikely because 
the transfer hoses used have multiple layers of rubber and a layer of braided stainless 
steel wire underneath the outer sheath (to prevent abrasions, cuts, and splits) it is 
more likely than the worst-case as required by 40 CFR 68.28(b)(i).  This scenario is also the 
most likely to occur, since  
overfilling is prevented by a return vapor line to the tank 
truck making the delivery.  The transfer hose rupture area is assumed at 0.5 square 
inches.  Because personnel are always present at the facility during transfer, CARGILL 
personnel will respond within 10 minutes.  Release rate was calculated using  
the OCAG tank release equation (Section 8.1.1).              
 
Input of the preceding data into DAGADIS+ revealed an alternative release scenario impact  
of 0.23 miles for the facility. There are no residences located within 0.23 miles from the facility.  
In fact, the closest residence is located approximately 0.4 miles away.  The amount of ammonia 
that would have to be released to reach this residence is as unlikely as the worst-case scenario.  
Thus, this alternative release scenario satisfies the conditions of 68.28.  There is no population 
impact from the alternative release scenario.    
 
The facility maintains written process safety information to enable employees invol 
ved in 
handling ammonia to identify and understand the hazards posed by this process.  Written 
information includes physical properties of ammonia, health risks associated with ammonia 
exposure, and material safety data sheets.  In addition, the facility has conducted and/or 
implemented the following: 
 
            hazards review 
            standard operating procedures 
            training program 
            maintenance program 
            compliance audits 
            incident investigation      
 
In August of 1997, the CARGILL AgHorizions anhydrous ammonia facility reported release of 
400 pounds when a hose broke on a nurse tank.  No injuries were sustained in the accident.           
 
Recommendations for safety improvements were identified in the hazard review which was 
completed March 6, 1999.  Recommendations were identified for two categories: Standard 
Operating Procedures, and Training.  Safety improvements will be investigated concerning their 
im 
pacts on other systems and/or procedures prior to implementation.  Additional 
recommendations may be made upon review of any accidents and/or when the hazard review is 
updated every five years.  
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