U.S. sanctions on North Korea have been in effect for decades and as a result, most American business leaders today have had to pay little or no attention to their impact or implications. In 2008, the North Korea sanctions program intensified and grew.

Now, the Trump administration appears to be further expanding prohibitions by specifically targeting Chinese firms. These conditions, called “secondary sanctions,” mean U.S. businesses could experience the economic effects of our strained relationship with North Korea for the first time.

{mosads}The current North Korea sanctions program blocks property interests and restricts the export and import of most goods, services, and technology to and from North Korea, both directly and indirectly. This includes items like military supplies and luxury goods, as well as gold, rare earth metals, coal and iron.

There are also North Korean and third-party entities that have been placed on restricted parties lists. This means that Americans are not allowed to do business with parties listed. Additionally, the U.S. Treasury Department has issued guidance advising individuals to act with caution when considering a transaction with a nonblocked entity when one or more blocked persons has ownership or control of the entity.

The practical intent of this is to require U.S. parties to know who their foreign partners are and if they have some kind of business relationship with North Korea. Recently, the U.S. government has specifically targeted Chinese entities linked to North Korean financial activities.

It prevented U.S. banks from holding corresponding accounts for a Chinese bank and has added a Chinese shipping company and two individuals to the restricted parties list. These “secondary sanctions” target non-U.S. persons, or third-country entities, that do business with entities listed on the restricted parties lists, also sometimes called “blocked parties.”

In pursuing foreign policy and national security goals, the White House has previously implemented other secondary sanctions programs, most notably with Iran. While the U.S. government can limit or prohibit any U.S. entity from doing business with a sanctioned party, each country’s sanction program is unique. The Iranian secondary sanctions is the most advanced secondary sanction program and are set out in numerous executive orders and acts of Congress.

So, what is the potential for the administration enhancing secondary sanctions regarding North Korea? The answer is high, as U.S. sanctions programs and restricted parties lists change regularly and often, which may be how the Trump administration plans on implementing tougher rules.

It is also within the authority of the Treasury Department’s Office of Foreign Asset Control to make changes to the existing program without notification or additional approvals. To provide a sense of how quickly things can change, until early 2016 Americans could invest in North Korea. While this may sound surprising, some Wall Street firms were investing in North Korea’s energy sector and other natural resources.

Ultimately, the question is how far will the Trump administration go to extend secondary sanctions, in light of North Korea’s recent actions. In 2016, President Obama tightened the North Korea sanctions program by halting U.S. investment, increasing export restrictions, and prohibiting the sale, supply, transfer or purchase to or from both North Korea and anyone acting behalf of the Workers’ Party.

Consequently, non-U.S. companies doing business with North Korea were forced to evaluate their customers and business relationships — which any insider will tell you specifically targeted Chinese companies, as China controls approximately 90 percent of all trade with North Korea.

As the Trump administration further tightens the sanctions program, particular with secondary sanctions, U.S. companies will need to begin evaluating whether their Chinese partners are in business with North Korea and to what extent.

This is reminiscent of the early days of the Iran secondary sanctions when U.S. entities had to be concerned about their European partners and their business ties. Now we are working our way towards the same concerns with our partners in China.

Doreen Edelman is a trade attorney and co-leader of the global business team at Baker Donelson. She has more than 25 years of experience advising companies on import and export compliance, foreign investment and global expansion.

The views expressed by contributors are their own and are not the views of The Hill.