A/HRC/42/41 business enterprises have a responsibility, first and foremost, to prevent harmful exposure through the elimination of toxic substances from their products and production processes to the maximum extent possible. If hazards cannot be eliminated, business enterprises should rigorously and systematically apply the hierarchy of hazard controls to prevent exposure (principle 4) and mitigate adverse impacts on health, with the provision of personal protective equipment the protection measure of last resort. Businesses should proactively investigate working conditions throughout their supply and value chains (see also principles 5 and 8). 39. Businesses should always ensure that their policies and practices protect the workers most at risk of exposure to toxic substances. Business enterprises have a responsibility to ensure that children, young workers and women who are pregnant, who have recently given birth or who are breastfeeding should never use or otherwise be exposed to toxic substances at work. Measures may include the adjustment of their working conditions and working hours, the opportunity to perform other appropriate work or offer of work at a different workplace if adjustments are not technically feasible or justifiable at the workplace in question. Special measures must be taken for the protection of workers in high-risk sectors such as mining, agriculture, construction, energy, the military, manufacturing and waste disposal, among others, from exposure to toxic substances. Principle 4 – Hazard elimination is paramount in preventing occupational exposures. Commentary 40. The most effective means to prevent exposure of workers to toxic substances is to eliminate them from the workplace. This is reflected in the good practice known as the hierarchy of hazard controls encouraged by ILO and national bodies concerned with occupational safety and health.36 In descending order of effectiveness in terms of preventing exposure, elimination is followed by risk mitigation options such as substitution with less hazardous substances and materials; engineering controls; administrative controls; and the use of personal protective equipment. 37 Efforts by ILO and others to improve occupational safety and health have evolved towards greater emphasis on the prevention of occupational accidents and diseases by eliminating the use of carcinogens and other chemicals of concern, complementing the more traditional prescription of protective measures to deal with specific hazards.38 41. As part of their occupational safety and health legislation, States should compel business enterprises to eliminate hazards wherever possible and apply the hierarchy where the hazard cannot be eliminated. States should ensure that these laws and policies are precautionary in practice because of the high level of scientific uncertainty that often prevails. Businesses should apply the hierarchy of hazard controls irrespective of whether it is required by law. Principle 5 – Duties and responsibilities to prevent the exposure of workers to toxic substances extend beyond borders. 42. The international transfer of dangerous and dirty work, whether extraction of natural resources, use of toxic chemicals and pesticides or disposal of hazardous wastes, without appropriate measures to protect workers against exposures to toxic substances has left workers, their families and their communities at considerable risk of grave impacts on their human rights. For example, as a result of globalization and other factors, chemical-intensive manufacturing and processing activities, once largely located in the highly industrialized 36 37 38 10 National Institute for Occupational Safety and Health, “Hierarchy of controls”, Centers for Disease Control and Prevention, 11 May 2018. Other good practices include the concept of “inherently safer design” where hazards are eliminated, rather than controlled. See Center for Chemical Process Safety, Inherently Safer Chemical Processes: A Life Cycle Approach, 2nd ed. (2009). A/33/41, para. 39. ILO Occupational Safety and Health Convention, 1981 (No. 155) and other occupational safety and health standards developed thereafter, including the Promotional Framework for Occupational Safety and Health Convention, 2006 (No. 187).