Code	Occupation Description (1980)	Total # Employees (Male & Female)	Total # Female Employees
549	NOT SPECIFIED MECHANICS AND REPAIRERS	464
563	BRICKMASONS AND STONEMASONS	185
599	CONSTRUCTION TRADES, N.E.C.	155
757	SEPARATING, FILTERING, AND CLARIFYING MACHINE OPERATORS	200
779	MACHINE OPERATORS, NOT SPECIFIED	184
849	CRANE AND TOWER OPERATORS	386
859	MISCELLANEOUS MATERIAL MOVING EQUIPMENT OPERATORS	464
865	HELPERS, CONSTRUCTION TRADES	126
889	LABORERS, EXCEPT CONSTRUCTION	850
TOTAL		3,013

*(1) The estimates for each occupation apply across the surveyed industries in which the agent was observed. Not all industries were surveyed, and not all agents were observed in all surveyed industries. (2) When using the estimates, 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.