He aha ka manaʻo o ka pae pahū-hōʻoia ABC

ʻO ka “abc” represents gas classifications, categorized into three levels—IIA, IIB, and IIC—according to the maximum experimental safe gap (MESG) or the minimum igniting current (MIC).

Kaulana Kūlana	Hoʻokaʻawale kinoea	Nā kinoea lunamakaʻāinana	ʻImi hoʻomāmā liʻiliʻi
Ma lalo o ka Mine	I	Methane	0.280mJ
Nā Hale Hana Ma waho o ka Mine	IIA	Propane	0.180mJ
	IIB	Ethylene	0.060mJ
	IIC	Hūhāhā	0.019mJ

Of these, the IIC classification is deemed the most hazardous, with IIB and IIA following in decreasing order of risk. Gases falling under the IIC classification include hydrogen, acetylene, kalapona disulfide, ethyl nitrate, and water gas. Those in the IIB category encompass ethylene, coke oven gas, propyne, a hydrogen sulfide. The IIA classification includes gases such as methane, ethane, benzene, a diesel.