WASHINGTON (Reuters) - The U.S. Commerce Department on Monday launched a national security probe into titanium sponge imports, a key input in military aircraft and other equipment like space vehicles, satellites, naval vessels, missiles and munitions.

The probe under Section “232” follows an investigation by the Commerce Department in 2017 to review if titanium sponge imports from Japan and Kazakhstan were injuring U.S. producers and was prompted by a petition from U.S.-based Titanium Metals Corp, part of Berkshire Hathaway Inc’s Precision Castparts Corp.

In 2017, the U.S. International Trade Commission voted to end its probe into the imports, saying it found no harm.

The Commerce Department said the Pentagon supported the national security probe.

“Titanium sponge has uses in a wide range of defense applications, from helicopter blades and tank armor to fighter jet airframes and engines,” said Commerce Secretary Wilbur Ross.

Titanium sponge is a porous form of titanium resulting from the first stage of processing the metal for use in the aerospace, electronic, architectural and sports equipment industries.

Titanium is also used in infrastructure and commercial products including civilian aircraft, chemical plants, oil and gas plants, electric power and desalination plants, building structures, automobile products and biomedical devices, the Commerce Department said.

Boeing Co and Airbus SE are major users of titanium sponge.

Imports account for more than 60 percent of U.S. titanium sponge consumption. Only one facility in the United States currently has the capacity to process titanium ore into the sponge used in manufacturing, the department said, adding that it was difficult to stockpile the material because it degrades.

In July, the department a launched national security investigation into uranium imports. The new probe is the fifth launched by the Trump administration under Section 232 of the Trade Expansion Act of 1962, previously a seldom-invoked Cold War-era law.

Probes on steel and aluminum imports have led to tariffs and quotas on the metals, prompting retaliation from trading partners including Canada, Mexico and the European Union.

The Commerce Department completed a Section 232 probe into automotive imports that could lead to a significant hike in U.S. tariffs for the sector. That probe’s findings were submitted to the White House last month, but have not yet been made public.