Add five U.S. airports and five seaports to the list of those with a great deal to fear because the tariff battle that went into effect Friday between China and the U.S. appears likely to escalate.

These five seaports and five airports, in particular, have a great deal to fear because like other airports and seaports, as well as the nation’s border crossings, they generate a significant percentage of their operating budgets from fees on imports, fees that are based on the tonnage of those imports rather than the value and paid by airlines and shipping lines.

While the impact will be felt broadly at airports and seaports across the nation, just the top five seaports account for more than two-thirds of that water-borne tonnage stamped Made in China and just the top five airports more than 70% of those products that are flying in. This is based on U.S. Census data through May, which was released Friday and which I analyzed.

While the tariffs levied on U.S. imports thus far have been relatively minor, on about $34 billion of more than $505 billion in 2017 imports, Trump has threatened that the tariffs could engulf almost all Chinese imports.

A larger tariff fight would not only affect revenues at the following seaports and airports but also the surrounding trade infrastucture — workers at the seaports and airports, truck drivers and train lines, customs brokers who help clear the imports, bankers involved in financing the trade, and more.

A quick rundown of those five seaports and five airports follows.

You can check on all gateways for U.S. total trade with China by clicking here and scrolling down to the port section. From there, you can toggle between airports and seaports as well as value vs. tonnage and the current month, 2017 or year-to-date data. The totals will include exports as well as imports.