Status effects for oxygen tank usage and condition drain:

                <StatusEffect type="OnWearing" target="Character" HideFace="true" ObstructVision="true" PressureProtection="10000.0" SpeedMultiplier="0.8" LowPassMultiplier="0.2" setvalue="true" disabledeltatime="true">
                    <Sound file="Content/Items/Diving/DivingSuitLoop1.ogg" range="500" />
                </StatusEffect>
                <StatusEffect type="OnWearing" target="Contained,Character" OxygenAvailable="-100.0" Oxygen="-20.0" Condition="-0.37">
                    <Conditional IsDead="false" />
                    <RequiredItem identifier="weldingfueltank" type="Contained" />
                </StatusEffect>
                <StatusEffect type="OnWearing" target="Contained,Character" OxygenAvailable="-100.0" Oxygen="-20.0" Condition="-0.37">
                    <RequiredItem identifier="incendiumfueltank" type="Contained" />
                    <Affliction identifier="burn" amount="0.1" />
                </StatusEffect>
                <StatusEffect type="OnWearing" target="Contained,Character" OxygenAvailable="1000.0" Condition="-0.15" comparison="And">
                    <Conditional IsDead="false" />
                    <RequiredItem identifier="oxygentank" type="Contained" />
                </StatusEffect>
                <StatusEffect type="OnWearing" target="Contained,Character" OxygenAvailable="1000.0" SpeedMultiplier="1.25" Condition="-0.16" comparison="And">
                    <Conditional IsDead="false" />
                    <RequiredItem identifier="oxygeniteshard" type="Contained" />
                </StatusEffect>
                <StatusEffect type="OnWearing" target="Contained,Character" OxygenAvailable="1500.0" SpeedMultiplier="1.35" Condition="-0.04" comparison="And">
                    <Conditional IsDead="false" />
                    <RequiredItem identifier="oxygenitetank" type="Contained" />
                </StatusEffect>
                <!-- We get to define item-side effects for once so might aswell make use of it -->
                <StatusEffect type="OnWearing" target="Contained,Character" OxygenAvailable="1000.0" Condition="-0.05" comparison="And">
                    <Conditional IsDead="false" />
                    <RequiredItem identifier="tag_oxygencell1" type="Contained" />
                </StatusEffect>
                <StatusEffect type="OnWearing" target="Contained,Character" OxygenAvailable="1500.0" Condition="-0.03" comparison="And">
                    <Conditional IsDead="false" />
                    <RequiredItem identifier="tag_oxygencell2" type="Contained" />
                </StatusEffect>

Inventory code:

            <ItemContainer capacity="1" maxstacksize="1" slotsperrow="2" hideitems="true" containedstateindicatorslot="0" containedstateindicatorstyle="tank">
                <ContainedStateIndicator texture="Content/UI/ContainerIndicators.png" sourcerect="0,96,120,24" />
                <Containable identifiers="oxygentank,weldingfueltank,oxygeniteshard,oxygenitetank,incendiumfueltank,oxygensource" />
                <SlotIcon slotindex="0" texture="Content/UI/WeaponUI.png" sourcerect="64,961,32,22" origin="0.5,0.45" />
                <StatusEffect type="OnWearing" target="Contained">
                    <RequiredItem identifier="oxygensource" type="Contained" matchonempty="true"/>
                    <Conditional condition="lt 5.0" />
                    <Sound file="Content/Items/WarningBeep.ogg" range="500" />
                </StatusEffect>
                <SubContainer capacity="3" maxstacksize="8">
                    <Containable items="smallitem" excludeditems="toolbelt,toolbox,bandolier,cargoscooter" />
                </SubContainer>
            </ItemContainer>