It’s been banned on Oahu since 1973, but now the Dept. of Heath has outlawed the burning of trash on all of the islands. 

From DOH:

Open burning creates an unnecessary nuisance and possible health risk due to the smoke and air pollution it produces. The practice also creates a significant fire hazard. With the greater availability of alternative means of waste disposal such as improved trash services, recycling, and composting on all islands, backyard burning is no longer a necessity. Those violating the open burning rules are subject to fines of up to $10,000 per violation, per day.

You can find out more here.