The United States and 11 other Pacific Rim countries finally reached a deal on the Trans-Pacific Partnership (TPP), a massive free-trade pact.

After years in the making, the U.S. announced on Monday that it has settled on an agreement with 11 Latin American and Asian countries that will change the global economy.

"We have successfully concluded the Trans-Pacific Partnership," U.S. Trade Representative Michael Froman said Monday, reports CNNMoney.

Under the deal, the prices of tariffs and import quotas would become cheaper, making it is easier to import and export goods between the 12 countries. TPP would also open new Asia-Pacific markets to American businesses.

In addition to defining President Barack Obama's legacy, the partnership would affect 40 percent of the world economy, reshape industries and influence a wide range of goods, including the price of cheese and the cost of cancer treatments, reports Reuters. However, before TPP can take effect, it must first be ratified by the U.S. Congress and approved by lawmakers in other TPP countries.

President Barack Obama and Republicans who support the deal say it would expand trade and investment for the U.S. while giving U.S. exports and small businesses a boost, which would lead to well-paying jobs at home.

However, trade unions, environmental groups and opponents argue that it would send American jobs overseas and put American workers in direct competition with low-paid workers in other countries. They also say the deal champions corporate interests and lobbyist groups and could jeopardize Internet freedom, labor rights, access to affordable medicine and the safety protections that keep food and water clean.

Following the announcement, Democratic presidential candidate Bernie Sanders blasted TPP, arguing that it would cut U.S. jobs and hurt consumers as American companies seek out lower wage workers in developing economies.

"Wall Street and other big corporations have won again," said the Vermont Senator in a statement. He also vowed that he would "do all that I can to defeat this agreement" in Congress."

"It is time for the rest of us to stop letting multinational corporations rig the system to pad their profits at our expense," he said.

Meanwhile, Senate Finance Committee Chairman Orrin Hatch said warned that the TPP might fail to break down trade barriers for American-made products.

"While the details are still emerging, unfortunately I am afraid this deal appears to fall woefully short," said the Republican senator.