IN a number of Asian countries, fly ash-fly bottom ash (FABA) are categorized differently. South Korea classifies it as ordinary waste, while Japan includes it on the list of toxic waste. Meanwhile, Malaysia has designated it as hazardous waste. What these countries have in common is that they have long allowed the use of FABA, generally for a mixture of building materials and pavers.

Anggoro Tri Mursito, researcher at the Geotechnology Research