If you need to add a substance to an assessment, but don't have the SDS to upload to the substance library, you can make an SDS request inside your Sevron System Account.

Please see the following video:

How do I Request an SDS from My Substance Inventory?
​http://helpcentre.sevron.co.uk/en/articles/1537590-how-do-i-request-an-sds-from-my-substance-inventory