A kind of Karmādāna (occupation involving great bondage of Karma);
the industry in which tremendous violence to the fire-bodied beings (in furnace etc) is committed - the industry such as manufacturing or trading in coal.
Iṃgālā niddahituṃ vikkiṇati.
(ĀVaHāVṛ 2 p.226)
Aṅgāraṇāṃ karaṇavikrayasvarūpam, evamagnivyāpārarūpaṃ yadanyadapīṣṭakāpākādikaṃ karma tadaṅgarakarmocyate.
(Bhaga 8-242 Vṛ)