In the event of an indoor natural gas leak, the primary safety procedures involve immediate evacuation, eliminating ignition sources, and ensuring proper ventilation. Here's a breakdown:

1. Evacuation: Immediately evacuate the area, including downwind locations, to a safe distance. Only trained personnel should respond to the emergency. LLMCitation(cited_text_snippet='Personal Precautions: Evacuate the area immediately. Isolate the hazard area. Keep out unnecessary and unprotected personnel. Evacuate downwind locations.', source_document_reference_number=1) LLMCitation(cited_text_snippet='Only trained personnel should respond to an emergency involving LPG. Other personnel should be evacuated at a safe distance located upwind.', source_document_reference_number=2) 2. Eliminate Ignition Sources: Eliminate any potential ignition sources such as open flames, sparks, static discharge, and heat. Use only grounded, explosion-proof equipment. LLMCitation(cited_text_snippet='Eliminate heat and ignition sources such as sparks, open flames, hot surfaces and static discharge.', source_document_reference_number=1) Distant ignition and flashback are possible. LLMCitation(cited_text_snippet='Eliminate all ignition sources.', source_document_reference_number=1) 3. Ventilation: Ensure adequate ventilation by opening windows and doors if it is safe to do so, to allow the gas to dissipate. 4. Leak Detection: Do not use a flame to detect leaks. Soapy water may be used to check for leaks. Use a compatible flammable gas detector to determine the presence and concentration of flammable gas in an indoor location. LLMCitation(cited_text_snippet='Do not use a flame to detect a leak. Soapy water may be used to test if a cylinder is leaking. Use a compatible flammable gas detector to determine the presence and concentration of flammable gas in an indoor location.', source_document_reference_number=2) 5. Contact Emergency Services: Contact emergency services and the manufacturer/supplier for advice and assistance. LLMCitation(cited_text_snippet='Contact emergency services and manufacturer/supplier for advice.', source_document_reference_number=1) 6. Reporting: Report spills to local health, safety, and environmental authorities as required. LLMCitation(cited_text_snippet='Report spills to local health, safety and environmental authorities, as required.', source_document_reference_number=1)

It's important to have detailed safety procedures that include information about inspection, connection and disconnection, and what to do in case of a flammable gas release. LLMCitation(cited_text_snippet='The safety procedures should include detailed information about inspection, connection and disconnection procedures, and what to do in case of a release of flammable gas in the air.', source_document_reference_number=5) Regularly inspect the transfer hose assemblies for leaks or damage, and if any are found, remove them from service until they are repaired or replaced. LLMCitation(cited_text_snippet='Before each use, inspect the transfer hose assemblies for leaks or damage. If leaking or damaged, do not use them and remove them from service until replaced or repaired.', source_document_reference_number=5)

Only trained personnel should handle emergencies involving LPG. LLMCitation(cited_text_snippet='Only trained personnel should respond to an emergency involving LPG.', source_document_reference_number=2) If a cylinder is leaking, try to tighten the valve and tag the cylinder as damaged, then store it in a well-ventilated area and contact the supplier for instructions. LLMCitation(cited_text_snippet='If a cylinder leaks, tighten the valve, attach a tag indicating that the cylinder is damaged and contains flammable gas, and store it in a well-ventilated area. Contact the supplier for instructions on returning the cylinder.', source_document_reference_number=9)

In case of a fire, if it is safe to do so, shut off the gas supply. LLMCitation(cited_text_snippet='In case of a fire caused by flammable gas, shut off the gas supply to extinguish the fire if it is safe to do so.', source_document_reference_number=9)