You should:
Gather information about the hazardous properties of the substances, the work, and the working practices (or find out what the problems are)
Evaluate the risks to health
Decide on the necessary measures to comply with Regulations 7-13 of COSHH
Record the assessment (if you have 5 or more employees)
Decide when the assessment needs to be reviewed
You can find more information on carrying out a COSHH risk assessment in the HSE publication [A step by step guide to COSHH assessment](http://books.hse.gov.uk/hse/public/saleproduct.jsf?catalogueCode=9780717627851).