A/HRC/39/48 include the unreasonably high burden of proof, the long latency periods for consequences to manifest in some cases and the difficulty in establishing causation; substantial information gaps with respect to the identification of hazards, measurement of exposure and specification of the epidemiological impacts; possible exposure to a multitude of different substances in various occupational settings and over a working lifetime; and the provisions of contractual relationships between suppliers and purchasers which can shift responsibility up or down a supply chain. 71. The types of information required and the responsibility for proving the cause of harms suffered are often common denominators in cases where workers struggle to access effective remedies. Workers often lack the necessary knowledge and resources to enable them to establish the necessary elements for accessing remedies. First, it is not uncommon for them not to know to which substances they were exposed. Second, substances to which they were exposed may not have been studied for their ability to cause disease or disability in humans; adequate information, and even a minimal amount of health and safety data, is lacking for tens of thousands of potentially hazardous industrial chemicals. Third, when allegations of exposure to hazardous substances are made, “objective evidence of the extent of, or even the existence of, exposure, is almost never available”,66 although it should be the responsibility of the employer to track and maintain such data, and the failure to do so is used to justify the unacceptable denial of remedies to sick and impaired workers. Finally, workers often move between employers and industries, which can subject them to diverse hazardous exposures. The personal behaviour of workers, such as tobacco or alcohol use, may be invoked to further complicate the determination of causation. IV. Conclusions and recommendations 72. The exposure of workers to toxic substances can and should be considered a form of exploitation and is a global challenge, with countries of all levels of development playing a role in the problem. States, business actors and international organizations can eliminate or minimize exposures and must do so with urgency. 73. The Special Rapporteur offers 15 principles to help States, business enterprises and other stakeholders protect, respect and fulfil the human rights of workers that have been infringed by their occupational exposures to toxic and otherwise hazardous substances. They are grounded in international human rights law and build upon the Guiding Principles on Business and Human Rights, ILO instruments and international agreements on toxic chemicals and wastes, among others. 67 These principles are the outgrowth of cases brought to the attention of the mandate since its inception in 1995. 74. In his view, if implemented, these principles will help strengthen the coherence between human rights and occupational health and safety standards regarding the exposure of workers to toxic substances. They are not intended to be definitive, but mark the beginning of a process to clarify the duties and responsibilities of all parties. 75. In the coming months, the Special Rapporteur will gather input from States and other stakeholders regarding how these principles are reflected in their laws, policies and procedures, as relevant, on occupational exposure. He plans to present a more elaborated set of principles to the Human Rights Council at a future session of that will provide a framework for implementation by States, business enterprises and other actors. The Special Rapporteur encourages ILO and WHO to continue their efforts and for ILO in particular to seek to reflect these principles in its efforts to review and revise its conventions and standards on occupational safety and health. 66 67 McElveen, “Establishing proof of exposure”. For example, recommendations adopted by the International Conference on Chemicals Management (SAIGM/ICCM.3/15) and recommendations of an international workshop on hazardous substances in the lifecycle of electrical and electronic products held in Vienna in 2011 (SAIGM/OEWG.1/11). 15