Lake Hefner Water Treatment Plant - Executive Summary

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

We have adopted this Program in order to implement 40 C.F.R. 68, the federal requirements regulating Risk Management of Highly Hazardous Chemicals. 
This Program will help prevent the occurrence of, or minimize the consequences of, catastrophic releases by stating our policies and procedures for the management process hazards in start-up, operation, inspection, maintenance, and the other matters addressed in the federal standard. 
Our program calls for the maximum employee participation and includes all the elements of the employee participation provisions of the standard.  We will at a minimum: (1) consult with employees and their representatives on the conduct and development of the process hazard review and other elements of the risk management plan, and (2) provide to our employees and their representatives access to the process hazard review and all other information required to be developed under that standard. 
Accidental Release Prevention and Emergency Response Policies 
The C 
ity of Oklahoma City believes that preventative maintenance is the key to minimizing the potential for accidental releases.  Standard Operating Procedures (SOPs) have been reviewed and revised to enable the employees to perform their work in a safe and efficient. 
The Lake Hefner Water Treatment Plant has chosen to be a non-responding facility in the event of an emergency.  Responsibility for emergency response to an accidental release has been given to the Oklahoma City Police and Fire Departments and the State and Local Emergency Response Centers. 
Stationary Sources and Regulated Substances. 
The Lake Hefner Water Treatment Plant utilizes chlorine and ammonia as disinfectants for the treated drinking water.  The maximum inventory and threshold quantities for these chemicals are shown below. 
Chemical                                  Maximum Inventory (lb.)             Threshold Quantity (lb.) 
Chlorine                                                40,000                              
Anhydrous Ammonia                           22,800                                      10,000 
Offsite Consequence Analysis 
The offsite consequent analysis includes a worst-case scenario and an alternative release scenario as defined in 40 C.F.R  68.   RMP*COMP was used to determine endpoint distances for both scenarios.  A dense gas model is required since chlorine is heavier than air.  The models input parameters are summarized in the table below.  Ammonia is not heavier than air, however, the RMP*COMP program was also used for the model of ammonia. 
RMP*COMP Input Parameters 
            Worst-Case Scenario-Chlorine     Alternative Scenario-Chlorine       Alternative Scenario-Ammonia 
Windspeed (m/s)                     1.5                                 3                                                     3 
Atmospheric Stability Class        F                                 D                                                     D 
Temperature (0 F)                
     77                               77                                                    77 
Humidity (%)                             50                               50                                                    50 
Height of Release (m)                 0                                 1                                                      1 
Surface Roughness                   0.1                              0.1                                                  0.1 
End Point (mg/l)                       0.0087                        0.0087                                              0.140 
The results of the air dispersion model area summarized in the table along with estimated population within the impact area.  The population data was estimated using the Block  Centroid Density Group Method in Landview for the worst-case scenario.  
RMP*COMP Output Results 
              Worst Case Scenario-Chlorine    Alternative Scenario-Chlorine    Alternative Scenario-Ammonia 
t Radius (miles)              1.3                                 0.3                                                  < 0.1 
Estimated Pop. in Impact Area  10,100                        1,835                                               < 1,000 
Process Safety Management Program 
The City of Oklahoma City has compiled a Process Safety Management Program to minimize releases.  This Program includes; safety information on the covered chemicals, hazard reviews, operating and maintenance schedules, training, compliance audits, incident investigations, and emergency response procedures. 
Five-year Accident History 
In the last 5 years the Lake Hefner Water Treatment Plant has had 1 reported accident that led to the injury of an employee. The release in question occurred on February 28, 1997 at 2:00pm.  It involved an employee inhaling chlorine gas when the saddle on one of the 1-ton chlorine drums came off and sprayed the employee with chlorine gas.  There have been no other accidental rel 
eases from the covered processes that resulted in deaths, injuries, evacuations, sheltering-in-place, property damage, or environmental damage.
Click to return to beginning