Crew members on these ships are required to make four phone calls to government agencies and emergency response teams within thirty minutes of a spill.
The Sacramento Bee began investigating after the November Cosco Busan oil spill, in which the crew failed to make the calls on time.
The paper found that inspectors only check a tiny number of ships each year.
Last year, in about seven percent of the cases, crew members couldn't find the emergency phone numbers, or didn't understand what they were supposed to do with them.