B757 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 250; Flight Crew Total 31500; Flight Crew Type 4800
Situational Awareness
No Specific Anomaly Occurred All Types
Flight Crew Took Evasive Action
Human Factors; Manuals
This is the second occasion I have experienced what appears to be an unsafe loading of a combination of dangerous goods in the same cargo compartment.  Today; compressed oxygen; aircraft alkaline batteries; and flammable aerosol gas were all loaded in the aft cargo compartment. Any malfunction from batteries could ignite the flammable gas which then could lead to explosion of the O2 cylinders. This would cause a pure O2 environment and would certainly overwhelm the fire fighting capabilities of the cargo compartment. We contacted Dispatch and they were able to reach a Dangerous Goods Specialist who stated this was a legal loading. We did not agree and requested the dangerous goods be separated. This was accomplished causing a delay in the departure. We received planned dangerous goods info 18 minutes prior to departure and worked this issue as quickly as possible. On another occasion lithium metal batteries were loaded in the same cargo compartment as oxygen cylinders.  Once again we contacted Dispatch. Nobody answered the Dangerous Goods Hotline and the Dangerous Goods Manager did not answer the phone. In this case the Dispatcher went to his Manager and the decision was made to separate the lithium batteries from the oxygen cylinders. I would like some feedback on the reasoning that it is acceptable to load very volatile materials in the same cargo compartment as oxygen cylinders. There does not seem to be any common sense for doing this.  I understand that it is appropriate to carry such items but to have them in the same compartment as oxygen cylinders creates a potentially dangerous environment when it is not necessary.
B757 Captain questions the wisdom of loading compressed oxygen; aircraft alkaline batteries; and flammable aerosol gas in the aft cargo compartment; even though it is apparently legal to do so.