Chairwoman Annette Yamaguchi said the boulders are four to six feet high and are clinging to the mountainside.

"The erosion over the years has definitely taken its toll on that hill," Yamaguchi said. "I truly believe, as do some others, that if we get one monsoon rain, they could come crashing down.

"We are talking about some pretty darn big boulders. It looks like only tree roots may be holding them in place."

Rockslide concerns have emerged around the state. Last month, a rockslide along Kalaniana'ole Highway in the Makapu'u area spurred Waimanalo residents to ask the state for temporary measures to protect drivers.

State Department of Transportation spokeswoman Marilyn Kali said a $1.3 million study being compiled by consultant Park Engineering will give a few options for that rockslide area, including moving the road farther away or installing protective fencing, something similar to what was done after last year's Waimea Bay rockslide along Kamehameha Highway.

The state realigned a quarter-mile stretch of Kamehameha Highway near the Sunset Beach side of Waimea Bay after a March 6, 2000, rockslide closed the road.

State transportation officials are awaiting a separate statewide survey due this summer or fall on 30 potential rockslide areas along Hawai'i highways.

Earth Tech Engineering & Environmental Services, which designed the Kamehameha Highway realignment, is doing the $290,000 study.

After all the rockslide sites have been surveyed, the company will come up with safety options for each area.

Officials have already identified five areas as dangerous: the stretch of Kamehameha Highway near Waimea Bay; Kalaniana'ole Highway near Lana'i Lookout at Makapu'u; Kalaniana'ole Highway near Paiko Drive in Kuli'ou'ou; Kamehameha Highway near Waiale'e Bridge north of Sunset Beach; and Pali Highway near Castle Rock.

DOT officials say Waipahu Street is a city road and therefore not under state jurisdiction. City officials said they would look into the situation.

Yamaguchi said moving the road or placing protective fencing are not options in this case, and she will ask the city to have engineers survey the site to find a way to prevent a rockslide from occurring.