*(1) The estimates for each occupation apply only to the 3- and 4-digit SICs surveyed within the 2-digit SIC where the agent was observed. Not all SICs were surveyed, and not all agents were observed in all surveyed SICs. (2) When using the estimated numbers of exposures, standard errors associated with estimates should be considered. (3) Potential exposures to a chemical agent are categorized as actual (i.e., the surveyor observed the use of the specific agent) or tradename (i.e., the surveyor observed the use of a tradename product known to contain the specific agent). The estimates presented in the table combine both categories. (4) For a given occupation, the estimated number of potential exposures is not necessarily equal to the estimated total number of potentially exposed workers. For example, a worker may be exposed to the same agent from multiple sources; thus, it is not the worker that is controlled but the exposure. (5) The presence or absence of controls does not imply that controls are necessary or required. The estimates and the controls are strictly based on observations associated with potential exposures.