To develop a Process Safety Management (PSM) policy for ammonia, focus on preventing or minimizing the consequences of catastrophic releases of toxic, reactive, flammable, or explosive chemicals 2, 4. Here's a breakdown of key areas to address:

1. Hazard Analysis:

• Conduct a thorough Process Hazard Analysis (PHA) to identify potential hazards associated with handling ammonia 5, 6. The PHA should analyze potential causes and consequences of fires, explosions, or releases 5, 6.
• Consider equipment, instrumentation, utilities, human actions, and external factors that could impact the process 5, 6.
• Prioritize PHAs based on the potential to affect the largest number of employees and the severity of a potential release 13, 19.

2. Operating Procedures:

• Develop clear, technically accurate, and understandable operating procedures for tasks, data recording, operating conditions, and safety precautions [1].
• Ensure procedures include specific instructions, safety precautions, and information on safety implications [1].
• Review and revise procedures periodically to reflect current operations [1].

3. Pre-Startup Safety:

• For new processes, use the PHA to improve design and construction [2].
• Complete P&IDs, have operating procedures in place, and ensure staff is trained before startup [2].
• Evaluate initial startup and normal operating procedures as part of the pre-startup review [2].

4. Mechanical Integrity:

• Establish a mechanical integrity program to ensure the continued integrity of equipment [2].
• Include identification and categorization of equipment, inspections and tests, maintenance procedures, training, and documentation [2].
• Maintain equipment to minimize the risk of releases [2].

5. Managing Change:

• Define 'change' to include modifications to equipment, procedures, raw materials, and processing conditions [3].
• Establish procedures to manage changes, including temporary changes [3].
• Use a change form to document the description, purpose, technical basis, safety considerations, and required approvals [3].

6. Emergency Preparedness:

• Develop and implement an emergency action plan, including evacuation procedures [4].
• Establish an emergency control center for communication and coordination during emergencies [4].
• Equip responders with appropriate safety and health protections, led by a competent incident commander [4].

7. Compliance Audits:

• Select a trained individual or team to audit the PSM system [4].
• Evaluate the design and effectiveness of the PSM system and conduct field inspections [4].

8. Employee Involvement:

• Consult with employees and their representatives in developing and implementing PSM program elements and hazard assessments [5].
• Train and educate employees and inform them of incident investigation findings [5].

9. Equipment and Systems:

• Ensure all appurtenances are approved and comply with relevant standards [6].
• Use containers with a minimum design pressure of 250 p.s.i.g. for nonrefrigerated containers [7].
• Equip filling connections with back-pressure check valves and excess-flow valves [7].

10. Safety Relief Devices:

• Provide containers with safety-relief valves [7].
• Ensure safety-relief valves are arranged to minimize tampering and have direct communication with the vapor space [8].

11. General Safety Measures:

• Provide at least two suitable gas masks in readily accessible locations [8].
• Install an easily accessible shower or a 50-gallon drum of water at stationary storage installations [8].
• Take precautions against damage to ammonia systems from vehicles [9].

12. Contractor Safety:

• If contractors are involved in activities near covered processes, ensure their activities are controlled [2].
• Use a permit system or work authorization system to keep informed of contractor activities [2].

By addressing these key areas, you can develop a comprehensive PSM policy for ammonia that protects employees and prevents catastrophic releases.