Tuesday, several Oregon Guard members recalled in court the assignment in Iraq that took them to the Qarmat Ali water treatment plant in 2004. Their case against the military contractor KBR alleges they were exposed to carcinogens during that period.

Rocky Bixby was one of a group of servicemen charged with guarding KBR employees working at and around Qarmat Ali in 2003. Bixby told the jury he’d always been in top condition until the 2004 deployment. Since then, he said he’s easily winded, and has developed a condition that prevents him from breathing through his nose. Other vets told of an orange substance they saw, identified as sodium dichromate.

Attorneys for KBR asked Bixby about other places he and his unit visited, places known for poor air quality. They also probed his family’s medical history, and when symptoms showed up.

Later, Dr. Arch Carson took the stand. He’s a toxicologist who interviewed and examined the soldiers. He says their symptoms lead him to believe the soldiers were exposed to sodium dichromate at very high levels. And, he added, there is no safe level of exposure to it.

Attorneys defending KBR have indicated they intend to argue the military, and the soldiers themselves, carried responsibility for preventing exposure.

This story originally appeared on Oregon Public Broadcasting.