Toll Brothers and its employees are committed to respecting human rights in accordance with the United Nations Guiding Principles on Economics and Human Rights. As part of this commitment, all employees are regularly trained in toll brothers` code of ethics and business conduct policies. In addition, all subcontractors are required to formally commit to complying with all national and local laws, as well as to complying with Toll Brothers` Code of Ethics and Business Policies. Click here to read our full human rights directive. Trenches in other areas of the site had collapsed several times during construction. The three days before the collapse, workers used trench boxes to protect themselves from the possibility of the ditch collapsing. .