Since 2002, at least 270 environmental accidents on U.S. Marine Corps bases on Okinawa have contaminated land and local waterways but, until now, few of these incidents have been made public. Internal reports highlight serious flaws in training and suggest the lessons of past accidents have not been effectively implemented. Moreover, recent USMC guidelines order service members not to inform Japanese authorities of accidents deemed "politically sensitive," raising concerns that many incidents may have gone intentionally unreported.