April 2013, Josh Fox released Gasland 2, his "international odyssey uncovering a trail of secrets, lies and contamination related to hydraulic fracking". It challenges the gas industry's portrayal of natural gas as a clean and safe alternative to oil as a myth, and that hydraulically fractured wells inevitably leak over time, contaminating water and air, hurting families, and endangering the earth's climate with the potent greenhouse gas methane. In 2014, Scott Cannon of Video Innovations released the documentary The Ethics of Fracking. The film covers the politics, spiritual, scientific, medical and professional points of view on hydraulic fracturing. It also digs into the way the gas industry portrays hydraulic fracturing in their advertising. In 2015, the Canadian documentary film Fractured Land had its world premiere at the Hot Docs Canadian International Documentary Festival. Research issues Typically the funding source of the research studies is a focal point of controversy. Concerns have been raised about research funded by foundations and corporations, or by environmental groups, which can at times lead to at least the appearance of unreliable studies. Several organizations, researchers, and media outlets have reported difficulty in conducting and reporting the results of studies on hydraulic fracturing due to industry and governmental pressure, and expressed concern over possible censoring of environmental reports. Some have argued there is a need for more research into the environmental and health effects of the technique. Health risks There is concern over the possible adverse public health implications of hydraulic fracturing activity. A 2013 review on shale gas production in the United States stated, "with increasing numbers of drilling sites, more people are at risk from accidents and exposure to harmful substances used at fractured wells." A 2011 hazard assessment recommended full disclosure of chemicals used for hydraulic fracturing and drilling as many have immediate health effects, and many may have long-term health effects. In June 2014 Public Health England published a review of the potential public health impacts of exposures to chemical and radioactive pollutants as a result of shale gas extraction in the UK, based on the examination of literature and data from countries where hydraulic fracturing already occurs. The executive summary of the report stated: "An assessment of the currently available evidence indicates that the potential risks to public health from exposure to the emissions associated with shale gas extraction will be low if the operations are properly run and regulated. Most