of understanding was signed between Sinopec and Aramco to strengthen the already existing ties between the companies and to improve their downstream operations. Unipec, a subsidiary of Sinopec, is an intermediary for banned Russian oil. Environmental and safety record In 2004, Sinopec prospected for oil in the 1,550 square kilometers of Loango National Park in southern Gabon and encountered criticism for what domestic and foreign environmental critics said were poor and damaging methods. Primatology professor Christophe Boesch of the US-based environmental organization, the Wildlife Conservation Society (WCS), criticized the use of dynamite and heavy machinery in exploration and road construction by Sinopec through park, noting that it might drive native gorillas deeper into the jungle, where they would be outside legal restrictions on hunting. Gabonese law states that industries can extract oil from national parks, but must rehabilitate them to the prior condition. Boesch, and other international experts, have suggested that Sinopec use other methods such as horizontal drilling to minimize its environmental footprint. Sinopec's activities in Gabon's national parks were suspended in September 2006, by the Gabonese national parks council. In 2007, Sinopec redid its earlier environmental study, this time in conjunction with the Gabonese environmentalist group Enviropass and the World Wildlife Foundation, winning high marks from Gabonese, Western, and Chinese conservation experts. Shortly thereafter, Sinopec resumed production with more environmentally friendly methods. On 21 December 2006, gas started leaking during the drilling of a test well by the Sinopec Southern Prospecting and Development Branch in Quingxi. 12,380 people were evacuated after the leakage occurred. It took at least three attempts and two weeks for the company to seal the leak. China's top environmental watchdog warned Sinopec in 2007 to stop operations at one of its oil fields due to chronic river pollution. Zhongyuan Oilfields Petrochemical Company, a unit of Sinopec, had failed to meet waste water treatment requirements and had been ordered to pay a pollution fine and operations had to be halted, according to the State Environmental Protection Administration (SEPA). Guangdong Provincial Environment Bureau (GPEB) had also issued a red sign warning to 19 companies, including Sinopec Guangzhou, in February 2008. By GPEB's standard, the companies that have involved in excessive emissions or caused serious environmental pollution accidents will be given the red sign warning and will be placed under strict supervision. On Wednesday, 28 July 2010, an explosion at an abandoned Sinopec plastics and chemicals factory