A new law has gone into effect today that requires chain restaurants in New York City to display a symbol next to food items that contain high levels of sodium. The symbol, a saltshaker in a black triangle, will be placed next to any food item on a menu that contains 2,300 milligrams or more of sodium, the equivalent of the daily recommended intake, according to the New York Times.

New York City Health Commissioner Mary Bassett said the warnings are necessary since the public is largely unaware of the amount of salt that is in processed and prepared foods. She noted that the majority of New Yorkers consume too much sodium, which can lead to high blood pressure, strokes and heart disease, "the leading cause of death in the United States and in our city."

The salt warnings represent the first high-profile public health policy pushed by Mayor Bill de Blasio and follows in the footsteps of his predecessor, Michael Bloomberg, who targeted soda, trans fats and smoking, as well as required restaurants to post calorie counts on their menus, according to the Wall Street Journal.

First proposed in June, the New York City Board of Health unanimously approved the salt measure in September.

The law doesn't apply to all restaurants, only ones that operate within the city and have more than 15 franchises active nationwide, as well as concession stands at some movie theaters and ballparks. If any of the restaurants or vendors who fall under this rule fail to display the warnings by the March deadline, the owners will be fined $200.

As expected with a law of this nature, it has already been greeted with anger, reported Politico. The National Restaurant Association launched legal action against the law Monday, arguing that it goes "too far, too fast for New York's restaurant community."

"While the Board of Health thinks they are targeting corporate chains, in reality they are dealing yet another blow to many of New York's small businesses that have been working and continue to work hard to provide nutritional access to their customers," said Christin Fernandez, spokesperson for the National Restaurant Association.