(biostatistics, epidemiology, toxicology)); Health Hazards (Biological, Chemical and Physical hazards, Ergonomics and Human Factors); Working Environments (Mining, Industrial, Manufacturing, transport and storage, service industries and offices); Programme Management Principles (professional and business ethics, work site and incident investigation methods, exposure guidelines, Occupational exposure limits, jurisdictional based regulations, hazard identification, risk assessment and risk communication, data management, fire evacuation and other emergency responses); Sampling, measurement and evaluation practices (instrumentation, sampling protocols, methods or techniques, analytical chemistry); Hazard Controls (elimination, substitution, engineering, administrative, PPE and Air Conditioning and Extraction Ventilation); Environment (air pollution, hazardous waste). However, it is not rote knowledge that identifies a competent occupational hygienist. There is an "art" to applying the technical principles in a manner that provides a reasonable solution for workplace and environmental issues. In effect an experienced "mentor", who has experience in occupational hygiene is required to show a new occupational hygienist how to apply the learned scientific and management knowledge in the workplace and to the environment issue to satisfactorily resolve the problem. To be a professional occupational hygienist, experience in as wide a practice as possible is required to demonstrate knowledge in areas of occupational hygiene. This is difficult for "specialists" or those who practice in narrow subject areas. Limiting experience to individual subject like asbestos remediation, confined spaces, indoor air quality, or lead abatement, or learning only through a textbook or “review course” can be a disadvantage when required to demonstrate competence in other areas of occupational hygiene. Information presented in Wikipedia can be considered to be only an outline of the requirements for professional occupational hygiene training. This is because the actual requirements in any country, state or region may vary due to educational resources available, industry demand or regulatory mandated requirements. During 2010, the Occupational Hygiene Training Association (OHTA) through sponsorship provided by the IOHA initiated a training scheme for those with an interest in or those requiring training in occupational hygiene. These training modules can be downloaded and used freely. The available subject modules (Basic Principles in Occupational Hygiene, Health Effects of Hazardous Substances, Measurement of Hazardous Substances, Thermal Environment, Noise, Asbestos, Control, Ergonomics) are aimed at the ‘foundation’ and ‘intermediate’ levels in Occupational Hygiene. Although the modules can be used freely without supervision, attendance at an accredited training course is encouraged. These training modules are available from OH Learning.com Academic programs offering industrial hygiene bachelor's or master's degrees in