Under REACH, certain information should be communicated to your suppliers, customers and public authorities.
Communicating with suppliers
Your company may wish to inform the supplier of how you will use the substance, in order that the supplier may include this use in their registration.
You are required to identify exposure scenarios and measures to control risks.
Communicating with customers
Safety Data Sheets must be supplied to your customers
You are required to inform your customers of the presence of Hazardous Substances contained in a concentration > 0.1 % weight by weight even if the total annual volume is less than 1t/year.
Communicating with authorities
The European Chemicals Agency