A federal investigation has preliminarily determined four major Chinese solar-cell manufacturers circumvented U.S. tariffs by rerouting portions of their operation through Cambodia, Thailand, Vietnam and, Malaysia, the Wall Street Journal reports. Solar panels from those countries account for about 80% of U.S. imports. The Commerce Department investigation, initiated in March, caused industry disruption; the Biden administration sought to mitigate that disruption by declaring a 24-month safe harbor period on solar panels imported from those countries and invoking the Defense Production Act to boost domestic production. Shortages of solar panels in the U.S. — also due to restrictions on the importation of enslaved labor goods from China — are slowing the expansion of renewable energy in the U.S. A final Commerce Department ruling, which will include on-site audits and public comments and could differ from the preliminary findings, will be released in May. (Wall Street Journal $)