Code	Occupation Description (1980)	Total # Employees (Male & Female)	Total # Female Employees
516	HEAVY EQUIPMENT MECHANICS	156
519	MACHINERY MAINTENANCE OCCUPATIONS	703
585	PLUMBERS, PIPEFITTERS, AND STEAMFITTERS	64
637	MACHINISTS	236
783	WELDERS AND CUTTERS	1,496
853	EXCAVATING AND LOADING MACHINE OPERATORS	781
855	GRADER, DOZER, AND SCRAPER OPERATORS	468
TOTAL		3,905

*(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.