Table 1 History of the preventive programme from 1980 through 1998.

Year	Control type	Description of control
Baseline status of facility at opening
1980	Engineering	Exhaust ventilation for powder handling
1980	Engineering	Enclosed, ventilated wet machining operations
1980	Engineering	On‐site laundry and locker rooms
1980	Engineering	HEPA‐filtered central vacuum system
1980	Administrative	Compressed air for cleaning and dry sweeping in production areas prohibited
1980	Administrative	Dry vacuuming and wet mopping performed at least weekly
1980	Administrative	End‐of‐shift showering and change of clothing required
1980	PPE	Facility uniforms (short‐sleeved jumpsuits) used
1980	PPE	Half‐face negative pressure respirators required for powder handling
Changes made before the 1992 survey
1984	Engineering	Enclosures added around some machines
1985–6	Engineering	Building expanded. Additional local exhaust ventilation added
1988	Administrative	Smoking, eating and drinking in production areas banned
Changes made between 1992 and 1998 surveys
1993–5	Engineering	Additional exhaust ventilation and enclosures added around machines
1995	Engineering	Locker rooms fully segregated (clean/dirty sides)
1995	Engineering	Water spray added over hamper to keep uniforms wet before laundering
1998	Administrative	Free‐standing man‐cooling (high‐velocity) fans prohibited in production areas

HEPA, high‐efficiency particulate air; PPE, personal protective equipment.