S & M Fertilizer & Seed Co., Inc. - Executive Summary |
|
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) Standard Industrial Classification (SIC) code Five-year accident history OHSA PSM (29 CFR 1910.119) applicability. This facility is regulated under Program 2 requirements under 40 CFR 68.10 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 SIC code specified in the rule It has not had a reportable accident in the past five years 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. S & M Fertilizer stores more than the threshold quantity of anhydrous ammonia (10,000 pounds) for commercial sale as fertilizer. Therefore, S & M Fertilizer is required to submit a Risk Management Plan (RMP) as defined in 40 CFR 68.150 by June 20, 1999. The S & M Fertilizer & Seed Co., Inc. is committed to operating in a safe and compliant manner. Employees involved in operating the ammonia storage and transfer facility are throughl y trained to identify and understand the hazards posed by this the transfer process. 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 S & M Fertilizer anhydrous ammonia storage and transfer facility. The facility has a stationary storage tank with capacity of 30,000 water gallons (145,000 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. S & M Fertilizer has chosen to use the DEGADIS+ to determine offsite impacts. Worst-Case Scenario Parameters 1. Land Use - Rural 2. Release Qty - 125,000 lb 3. Release Rate - 12 ,500 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: Largest Tank Capacity is 26,000 water gallons Liquid Ammonia Density = 5.67 lb/gal (www.nh3.com) Maximum Fill Volume = 85% capacity (Administrative Limit) Release Rate = Tank Capacity / 10 minutes = (26,000 gal * 5.67 lb/gal)*(0.85) / 10 min = (147,420 lb)*(0.85) / 10 min = 125,000 (rounded) / 10 min = 12,500 lb/min Input of the preceding data into DEGADIS+ Comp program, the results indicate a worst-case impact of 2.2 miles for the facility. The rule defines the toxic endpoint of anhydrous ammonia to be 0.14 mg/L. The residential population within a 2.2 mile radius of the facility is 600 (rounded) based on the 1990 US Census data (average population density is 41 people per square mile, worst-case area of influence is 15 square miles). 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 lay ers 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, S & M Fertilizer 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. Since there are residences approximately 0.23 miles from the facility, this alternative release scenario satisfies the conditions of 68.28. The population impact from the alternative release scenario is estimated at 7 people (from 1990 census data). The facility maintains written process safety information to enable employees involved 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 The S & M Fertilizer anhydrous ammonia has had no recordable accidents within the past five years. Recommendations for safety improvements were identified in the hazard review which was completed February 5, 1999. Recommendations were identified for two categories: Standard Operating Procedures, and Training. Safety improvements will be investigated concerning their impacts 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. |