All hexavalent chromium compounds are toxic (due to their oxidizing power) as well as carcinogenic (IARC Group 1), especially if airborne and inhaled where they cause lung cancer. Positive associations have also been observed between exposure to chromium (VI) compounds and cancer of the nose and nasal sinuses.[5] Workers in many occupations are exposed to hexavalent chromium. Problematic exposure is known to occur among workers who handle chromate-containing products and those who grind and/ or weld stainless steel.[6] Workers who are exposed to hexavalent chromium are at increased risk of developing lung cancer, asthma, or damage to the nasal epithelia and skin.[3] Within the European Union, the use of hexavalent chromium in electronic equipment is largely prohibited by the Restriction of Hazardous Substances Directive and the European Union regulation on Registration, Evaluation, Authorisation and Restriction of Chemicals.[citation needed]