Code	Occupation Description (1980)	Total # Employees (Male & Female)	Total # Female Employees
453	JANITORS AND CLEANERS	1,310
507	BUS, TRUCK, AND STATIONARY ENGINE MECHANICS	471
534	HEATING, AIR CONDITIONING, AND REFRIGERATION MECHANICS	1,610
549	NOT SPECIFIED MECHANICS AND REPAIRERS	3,258
585	PLUMBERS, PIPEFITTERS, AND STEAMFITTERS	2,780
633	SUPERVISORS, PRODUCTION OCCUPATIONS	133
724	HEAT TREATING EQUIPMENT OPERATORS	17
777	MISCELLANEOUS MACHINE OPERATORS, N.E.C.	1,275
783	WELDERS AND CUTTERS	2,729	744
784	SOLDERERS AND BRAZERS	118	100
785	ASSEMBLERS	5,724	1,432
796	PRODUCTION INSPECTORS, CHECKERS, AND EXAMINERS	162
TOTAL		19,589	2,276

*(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.