South Korea completed an environmental impact assessment of a US THAAD missile defense unit in a southern county Wednesday, the defense and environment ministries said, clearing the way for its full-fledged deployment.

The Yoon Suk Yeol administration has been pushing for the "normalization" of the Terminal High-Altitude Area Defense battery, which was installed in Seongju, 214 kilometers southeast of Seoul, in 2017, but has held the status of a "temporary" installation pending the assessment.

The normalization efforts have gained traction as North Korea has been doubling down on its nuclear and missile programs as seen in its major weapons tests earlier this year, including that of a solid-fuel intercontinental ballistic missile.

"Now that the environmental assessment has been completed through cooperation between the environment and defense ministries, we will closely cooperate with the US side to proceed with the (deployment) project in full reflection of the assessment," an environment ministry official was quoted as saying in a press release.

The environment ministry approved the environmental assessment document that the Defense Installations Agency under the defense ministry submitted May 11. The approval is expected to enable and expedite the infrastructure construction required for the full-capacity operation of the battery.

The assessment found the maximum amount of electromagnetic waves emanating from the THAAD base -- a key source of concern among local residents -- was just 0.2 percent of a legal safety protection standard, according to the ministries. To ensure credibility, the government involved third-party experts, like those from the Korea Radio Promotion Association, in the assessment.

"The environment ministry said it is judged that the impact of (the electromagnetic waves from the base) on human bodies and the surrounding environment is insignificant," the ministry said in a joint press release.

Although Pyongyang's missile provocations have underscored the need for such a missile defense unit, efforts for the full operation of the THAAD base have been hampered by protests by residents and activists amid lingering health concerns.

The installation of the THAAD battery here was also a bone of contention between Seoul and Beijing, as China argued it could undermine its strategic security interests amid an intensifying Sino-US rivalry. (Yonhap)