Honda EU20i Owner's Manual page 37

Batteries produce explosive gases: If ignited, and explosion can
cause serious injury or blindness. Provide adequate ventilation
when charging.
CHEMICAL HAZARD: Battery electrolyte contains sulfuric acid.
Contact with eyes or skin, even through clothing, may cause severe
burns. Wear a faceshield and protective clothing.
Keep flames and sparks away, and do not smoke in the area.
ANTIDOTE: If electrolyte gets into your eyes, flush thoroughly with
warm water for at least 15 minutes and call a physician
immediately.
POISON: Electrolyte is poison.
ANTIDOTE
External: Flush thoroughly with water.
Internal: Drink large quantities of water or milk.
Follow with milk of magnesia or vegetable oil, and call a
physician immediately.
KEEP OUT OF REACH OF CHILDREN.
2. Start the engine.
The DC receptacle can be used while the AC power is in use.
An overload DC circuit will trip the DC circuit protector (push button
comes out).
If this happens, wait a few minutes before pushing in the circuit
protector to resume operation.
DC CIRCUIT PROTECTOR
ON OFF
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