The amount of lead in the blood and tissues, as well as the time course of exposure, determine toxicity. Lead poisoning may be acute (from intense exposure of short duration) or chronic (from repeat low-level exposure over a prolonged period), but the latter is much more common.
The COO is responsible for the daily operation of the company, and routinely reports to the highest ranking executive, usually the chief executive officer (CEO). The COO is usually the second in command at the firm, especially if the highest ranking executive is the Chairman and CEO.
1 Chief operating officer, also called the chief operations officer, director of operations, or operations director.  Director of operations, a position responsible for controlling a large part of the operations of a company, subordinate to the chief operating officer (mainly found in complex or growing organizations).