On Thursday, a contractor for the US Environmental Protection Agency started an operation to remove barrels containing defoliants from Wallowa Lake in Oregon.

Last August, recreational divers Lisa Anderson and William Lambert came across barrels labeled as containing 2,4-D and 2,4,5-T, which are defoliants, chemicals that when sprayed on plants cause their leaves to fall off. The two defoliants combined are also known as Agent Orange.

"We didn't know they were there," Anderson told media outlets at the time. "When we dusted one off, we were shocked to see the words 'weed killer' on it."
According to the US Department of Veterans Affairs, Agent Orange was used by the US military between 1962 and 1975, when it was sprayed on trees and vegetation during the Vietnam War. Some veterans exposed to Agent Orange during military service later developed cancers and other health problems that have been found to be related to exposure to dioxin, a byproduct of Agent Orange production.
"Veterans who may have been exposed to Agent Orange include Veterans who were in Vietnam, the Korean Demilitarized Zone, on Thai Air Force bases, and who flew on or worked on C-123 Aircraft," the VA writes on its website.

According to Laura Gleim, a spokesperson for the Oregon Department of Environmental Quality, the barrel removal process is expected to take several days. The containers are under 90 to 140 feet of water, Gleim added, also noting that the lake's icy temperatures may hinder recovery efforts. A remotely operated vehicle equipped with cameras is expected to survey the site Friday.
​On Thursday, officials also confirmed that the Oregon town of Joseph, which obtains its drinking water from the lake, will continue to use a backup well to draw its water while the operation is underway. Joseph has already tested its waters for 2,4-D, which is the less toxic chemical and no traces were found in the drinking water. Water tests for 2,4,5-T in Wallowa Lake were conducted earlier this week.
State officials also told lake visitors that they "may continue with normal activities until further notice," Oregon Live reported. The lake is a popular destination for swimming and boating during the summer months.

However, some residents are still wary about getting into the lake before the test results for 2,4,5-T are complete.

"It doesn't sound right to me," Meg Bowen, who lives in Joseph and often kayaks on the lake, told Oregon Live. "We are not going to be in the lake until we get the results of the tests. That just seems prudent to me."