MILILANI -- Members of a Mililani-area homeowners' association found out they unknowingly created an environmental hazard when they thought they were making harmless mulch for landscaping.

Piles of decomposing wood chips line the entrance to Waikalani Woodlands in Mililani. The president of the homeowner's association said he asked a landscaping company to put them there temporarily to create mulch to beautify the grounds of the complex.

"We wanted the mulch to rotor till it in to condition the soil -- make this a nicely planted area as people come in to our facilities, our homes over here," association president Phil Sunada said.

The company that brought the woodchips was Imua Landscaping. They are cutting trees along the H-2 Freeway and have been cited by the state for improperly dumping green waste.

Environmental watchdog Carroll Cox has been keeping an eye on Imua's operations.

The wood chips are hot and actually smoking. They are a fire hazard and they have been placed on a hill right next to a stream. Envirowatch's Cox said that violates the Clean Water Act.

"It degrades the water, gets in the water, leaches out, raises the temperature, blocks it, kills everything in it," Cox said.

If there was heavy rain, and the chips blocked the stream causing flooding, Cox said the homeowners' association could be liable.

"Even though the intent may have been good, it's essentially wrong and improper," Cox said.

Sunada said they would begin removing the chips on Tuesday morning.