City officials said the amount of asbestos at Stabler's Point Rock Quarry is too little to pose a danger to public health.
"If we think there is a public safety concern, we will close the quarry. But we haven't seen a reason to do it," said Rorie Watt, chief engineer of the city's capital improvement projects.
In late July, a private contractor sent samples out for testing, which showed that a piece of rock from the Stabler's Point contained tremolite, the most dangerous form of asbestos, which can cause lung cancer and asbestosis, a pulmonary disease. One sample showed 5 percent of asbestos, far exceeding what the Environmental Protection Agency considers safe.
City officials said Stabler's Point has less than 1 percent of asbestos, compliant with the EPA's safety standard. Watt said the geologists the city has consulted said the quarry at Auke Bay is unlikely to contain a large amount of tremolite.
"Given the rock formation, it is much more likely to find chrysotile, a less dangerous mineral than tremolite," Watt said. "Positive identification can only be determined through microscopic analysis. We are still waiting for the results."
"We use the rock to fill harbors and pave the streets," Watt said. "It is used in areas that are not problematic. If there is a large concentration, you don't want to use it for a ball field."
The city also sent out 15 samples from the quarry for lab testing. Results of two samples, crushed rock from Miller Construction and Secon, showed no asbestos.
"It's more a problem of perception," Watt said.
But two contractors who had used rock from Stabler's Point are waiting for more test results before using the rock again. Secon is holding off on paving Commercial Boulevard with the rock.
Only Miller Construction is hauling rock from the quarry right now.
The Stabler's Point quarry, Juneau's major sources of rock for construction projects, produces about 50,000 to 75,000 tons per year.
The city has tested rock from Stabler's Point and Hidden Valley, the only two active quarries in Juneau. Watt said the city has seen no asbestos in the Hidden Valley quarry and a small amount of asbestos at Stabler's Point.
Watt said quarry employees should be better educated on worker safety.
"Quarry workers, regardless of asbestos, should wear respirators when it is dusty," Watt said.
The federal Mine Safety and Health Administration will provide training for local contractors. The agency also will send an industrial hygienist to Juneau to evaluate worker safety at the quarry.
Assembly member Merrill Sanford the city will adopt rules regulating asbestos, dust control and quarry operations in winter.
"We want to make sure it won't be a hazard," Sanford said.
I-Chun Che can be reached at email@example.com.