1.   As a result, thousands of large water systems identified unsafe levels of lead and many sought to remedy the problem.

2.   But technicians virtually never find an unsafe level in the home.

3.   By World Health Organization standards, Mexicans breathe unsafe levels of ozone an average of five hours a day all year.

4.   Cumulative, low-dose exposure to unsafe levels of arsenic can cause cancer in humans.

5.   Equally disturbing, many women taking cholesterol-lowering drugs still have unsafe levels of cholesterol.

6.   FAA officials, however, said the Boston Center was the only facility where unsafe levels of asbestos were found in air samples.

7.   How many diabetics kept their blood sugar and cholesterol below unsafe levels, and how many avoided hospital stays?

8.   However the risk is measured, all agree the problem is identifying those whose skills have deteriorated to an unsafe level.

9.   It senses when water pressure inside the tank is rising to unsafe levels.

10.   Now, the city goes into alert when levels of sulfur dioxide, particulate matter or ozone hit unsafe levels.