Industrial chemicals may contribute to environ- mental pollution (considered next), and they may be a direct hazard in the workplace where they are used, formulated or manufactured. There is a huge range of chemical types and many different industries may involve the use or manufacture of hazardous chemicals. In the broadest sense industrial exposure might include exposure to the solvents used in photocopiers and typists correction fluid. Although in general exposure is controlled by law, often by the setting of control limits. Realistic levels may still prove to be hazardous in the long term and acute exposure due to accidents will always occur. The long development time of diseases such as cancer often makes it difficult to determine the cause until sufficient of the workforce have presented with the disease for the association with the toxic compound to be made.