For Australian readers you would know that any hazardous chemical in your work place requires and MSDS and a chemical risk assessment.
Too many businesses I visit view chemical and haz subs management as an afterthought rather than an integral part of their purchasing process.
When developing your purchasing process, ensure that there is a section devoted to the purchasing of chemicals and other hazardous substances. You should work with the people using the chemicals to develop a list of standard substances and suppliers for purchase. Each supplier would need to provide current MSDS's and if possible a chemical risk assessment before any chemicals are supplied.
By determining set limits for purchasing stock you can ensure that you are not spending too much AND you have a better idea what quantities you are storing on site.
Far too many businesses have no idea what they have in their workshops/storage cupboards etc.