Preventive action can and is any number of things...
Have a good equipment inspection and maintenance program.
Have a good awareness and response program for potential chemical spills or releases (here in the states we call it HAZWOPER (Hazardous Waste Operations & Emergency Response), and you can find it at
www.osha.gov.
Initiate a recycling program, an energy control program, a hazardous materials management program, the list can go on from here.
The main thing to do is educate the workforce and MANAGEMENT of whatever programs you put into place.
Aside from the above you can get into engineering issues like the control of storm water runoff, your drain/sewage system, managing stack emissions, scrap management/minimization, electrical power distribution, waste water management, and other things along these lines.
What you can do is boundless. be sure to document and show improvment.
If anything else comes to mind I'll let you know.