During portions of interviews aired on Friday's broadcast of CNBC's "Last Call," U.S. Customs and Border Protection Office of Trade Executive Assistant Commissioner Annmarie Highsmith and Assistant Port Director for the Port of New York/Newark Edward Fox said that determining whether goods were made with forced labor in China's Xinjiang Province has been made difficult by the fact that China's government "has taken affirmative steps to obfuscate those supply chains and prevent businesses from learning the conditions under which those products are manufactured" and "Solar panels are a big issue."