A large explosion rocked a natural gas processing plant on the Washington-Oregon border Monday, injuring five workers, causing about 400 people to evacuate from nearby farms and homes, and emitting a mushroom cloud of black smoke that was visible for more than a mile.

The 8:20 a.m. blast at the Williams Northwest Pipeline facility near the Washington town of Plymouth, along the Columbia River, sparked a fire and punctured one of the facility’s two giant storage tanks for liquefied natural gas.