After Marine Corps Air Station Tustin closed I worked there, Hazmat company come in and dugg a hole 100 ft deap and 200 ft wide where the gas station was And where they fueled the aircraft for the contaminated soil. http://www.salem-news.com/articles/march132012/mcas-tustin-tk.php

http://articles.latimes.com/1989-05-22/local/me-490_1_hazardous-tustin-base-waste-sites one of the workers told us they could digg 500 ft and still find contaminated soil and every base is the same.