Articles 26–29 of the statute allow the court to form smaller chambers, usually 3 or 5 judges, to hear cases. Two types of chambers are contemplated by Article 26: firstly, chambers for special categories of cases, and second, the formation of ad hoc chambers to hear particular disputes. In 1993, a special chamber was established, under Article 26(1) of the ICJ statute, to deal specifically with environmental matters (although it has never been used).