In 1996, the gasoline additive MMT was introduced into Canada by Ethyl Corporation, a U.S. company, when the Canadian federal government banned the import of the additive. The U.S. company filed a lawsuit under Chapter 11 of NAFTA, demanding $201 million from the Canadian federal government and Canadian provinces under the Agreement on Internal Trade (AIT). They argued that the additive had not been conclusively linked to health risks and that the ban harmed their business. After concluding that the ban was a violation of the WIL, the Canadian federal government lifted the ban and agreed with the U.S. company on $13 million.  Studies conducted by Health and Welfare Canada (now Health Canada) on the health effects of MMT in fuels have found no significant health effects associated with exposure to these exhaust emissions. Other Canadian researchers and the U.S. Environmental Protection Agency disagreed, citing studies suggesting possible nerve damage.  The law was developed under President George H. W.
Bush as the first phase of his Enterprise for the Americas initiative. The Clinton administration, which signed NAFTA in 1993, believed it would create 200,000 jobs in the United States within two years and 1 million within five years, as exports play an important role in U.S. economic growth. The government expected a dramatic increase in U.S. imports from Mexico due to lower tariffs. President Bill Clinton signed it on December 8, 1993. It became active on 1 January 1994. On Friday, U.S. President Donald Trump, Canadian Prime Minister Justin Trudeau and outgoing Mexican President Enrique Peña Nieto signed the United States-Mexico-Canada Agreement (USMCA) at the G-20 summit. Trump celebrated with a tweet hailing the new trade deal as the end of the “terrible” North American Free Trade Agreement (NAFTA), which has been in place since Jan. 1, 1994. Speaking to reporters aboard Air Force One on their way back from the G20 summit in Buenos Aires, Argentina, where the new pact was concluded, Trump said: “Just so you understand if I`m doing this – if for some reason we`re not able to make a deal because of Congress, then Congress will have a choice. ” approve the new agreement or return to pre-1994 trade rules when NAFTA entered into force.
Proponents of NAFTA in the United States have stressed that the pact is a free trade agreement, not an agreement of the economic community.  The free movement of goods, services and capital it introduced did not extend to labour. By proposing what no other comparable agreement had attempted to do – opening up developed countries to “one big third world country” – NAFTA avoided the creation of common social and employment policies. Labour market and/or workplace regulation was reserved exclusively for national governments.  President Donald Trump promised during the election campaign to repeal NAFTA and other trade agreements that he considered unfair to the United States. On August 27, 2018, he announced a new trade agreement with Mexico to replace him. The U.S.-Mexico trade agreement, as it was called, would maintain duty-free access for agricultural products on both sides of the border and remove non-tariff barriers to trade, while further promoting agricultural trade between Mexico and the United States and effectively replacing NAFTA. Maquiladoras (Mexican assembly plants that collect imported components and produce goods for export) have become the symbol of trade in Mexico. They moved from the United States to Mexico, hence the debate about losing American jobs.
Revenues in the maquiladora sector had increased by 15.5% since the introduction of NAFTA in 1994.  Other sectors have also benefited from the free trade agreement, and the share of exports to the United States from non-border states has increased over the past five years [When?], while the share of exports from border states has decreased. This allowed for rapid growth in non-cross-border metropolitan areas such as Toluca, León and Puebla, all of which were more populous than Tijuana, Ciudad Juárez and Reynosa. Key NAFTA provisions provided for the phasing out of tariffs, tariffs and other barriers to trade between the three members, with some tariffs to be lifted immediately and others over periods of up to 15 years. The agreement ultimately ensured duty-free access to a wide range of industrial products and goods traded between the signatories. Domestic commodity status was granted to products imported from other NAFTA countries and prohibited any state, local or provincial government from imposing taxes or duties on such goods […].