Farmers Co-op Grain & Lumber Company - 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
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,
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
It stores anhydrous ammonia and propane in excess of the
A release from this facility could impact an offsite public
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
source that has more than a threshold quantity of a regulated substance
in a process, as determined under 40 CFR 68.115 Farmers Co-op Grain &
Lumber Company stores more than the threshold quantity of anhydrous
ammonia and propane (10,000 pounds) for commercial sale. Therefore,
Farmers Co-op Grain & Lumber Company is required to submit a Risk
Management Plan (RMP) as defined in 40 CFR 68.150 by June 20, 1999.
The Farmers Co-op is committed to operating in a safe and compliant
manner. Employees involved in operating the ammonia and propane storage
facility are thoroughly traine
d 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
and propane, process technology, process equipment, and emergency
The stationary source is the Farmers Co-op Grain & Lumber Company
anhydrous ammonia and propane storage facility. The largest ammonia
process group (e.g., largest storage tank or group of interconnected
tanks) has a storage capacity of 60,000 water gallons (280,000 pounds).
The total ammonia stationary storage capacity is 280,000 pounds. The
facility also stores numerous smaller transportable tanks (nurse tanks)
that are actually used in the fertilizer application process.
The facility also has 48,000 water gallons (176,000 pounds) of propane
is a single process. The total propane stationary storage capacity is
The facility is
required to complete one worst-case release scenario
per hazardous substance handled [68.165(a)(2)] to determine program
applicability. Farmers Co-op has chosen to use the DEGADIS+ release
model and RMP Comp (Version 1.06) to determine offsite impacts.
For this facility, a worst-case release would occur in the event that
the largest ammonia and propane storage tanks 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).
Ammonia release rate for use of DEGADIS+ is presented below:
Sample Ammonia Endpoint Calculation
Given: Storage Tank Capacity is 60,000 water gallons
ANSI K61.1 filling density = 56 % (of water wt.)
Release Rate = Tank Capacity / 10 minutes
=(60,000 gal * 8.345 lb/gal water)*(0.56) / 10 min
= (500,700 lb)*(0.56) / 10 min
= 280,000 (rounded) / 10 min
= 28,000 lb/min
for the worst-case propane release follow the same method.
Results of Worst-Case Ammonia Release Scenario
Input of the preceding data into the DEGADIS+ release model, the
results indicate a worst-case impact of 2.8 (rounded) miles for the
facility. The worst-case model output summary is included at the end
of this section. The rule defines the toxic endpoint of anhydrous
ammonia to be 0.14 mg/L.
The residential population within a 2.8 mile radius of the facility is
800 (rounded) based on the 1990 US Census data.
Results of Worst-Case Propane Release Scenario
Input of the preceding data into the RMP Comp program, the results
indicate a worst-case impact of 0.40 (rounded) miles for the facility.
The rule defines the explosive endpoint of propane to be 1 psi
overpressure. The residential population within a 0.40 mile radius of
the facility is 9 (rounded) based on the 1990 US Census data.
The facility is required to complete one alternate release scenario per
ated chemical 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.
The alternative scenarios 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, Farmers Co-op personnel will
respond within 10 minutes. Release rate was calculated using the OCAG
tank release equation (Section 8.
1.1). Propane release is calculated
with a similar equation found in the Risk Management Program Guidance.
Results of Ammonia Alternative Release Scenario
There are 3 people located within 0.23 miles from the facility. Thus,
this alternative release scenario satisfies the conditions of '68.28.
Results of Propane Alternative Release Scenario
Input of the preceding data into the RMP Comp program, the results
indicate an alternate case impact of 0.05 miles for the facility. The
residential population within this radius is 0
The facility maintains written process safety information to enable
employees involved in handling ammonia and propane to identify and
understand the hazards posed by this process. Written information
includes physical properties of ammonia and propane, health risks
associated with ammonia and propane exposure, and material safety data
sheets. In addition, the facility has conducted and/or implemented the
standard operating procedures
The Farmers Co-op Grain & Lumber Company anhydrous ammonia and propane
facility in Humphrey has had no recordable accidents within the past
Recommendations for safety improvements were identified in the hazard
review which was completed April 12, 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.