Nevada state inspectors found no blowing dust around excavated rock piles at the Yucca Mountain nuclear waste repository site, officials said Friday.
"We did not see any violations of the federal or state Clean Air Acts," said Allen Biaggi, an administrator with the state Environmental Protection Division.
An Energy Department spokesman in Washington, D.C., said the inspection showed Yucca Mountain work was being conducted safely.
DOE inspectors also will conduct tests next week around the rock piles for blowing dust and the potentially hazardous minerals silica and erionite.
The stepped-up attention to air quality at the repository site, which is 90 miles northwest of Las Vegas, follow allegations that former workers contracted silicosis and other chronic lung ailments during tunneling from 1994 to 1997.
The Energy Department last month began a program to screen former tunnel workers for lung disease. Workers and state officials have expressed concerns the rock piles contain erionite or other dangerous materials.
Sen. Harry Reid, D-Nev., on Friday continued his call for a work stoppage until safety questions are investigated.
"I'm extremely concerned for the workers who have apparently been exposed to silica from their work at the Yucca Mountain site," Reid said in a statement.
Biaggi said Thursday's inspections focused only on air quality outside the repository tunnel, and not the composition of dust or the makeup of the rock piles.
Biaggi said winds blew at up to 25 mph while two state inspectors visited the site Thursday.
"They found the piles in very stable condition," he said. "They did not observe any dust coming off these piles."
Biaggi said the state conducts annual air quality inspections at Yucca Mountain and has never found blowing dust at the site.