The Conception dive boat accident that killed 34 people on Labor Day was one of the worst maritime disasters in California history, but the safety lapses that led to it were hardly unprecedented.

For years, small passenger vessels have gone up in flames for a variety of reasons, prompting repeated calls by the National Transportation Safety Board to improve fire-safety measures.

But a Times review of federal documents spanning nearly 20 years shows that the U.S. Coast Guard, which has the sole authority to mandate safety measures, has often rejected the board’s recommendations.

The NTSB found that issues such as an electrical malfunction, a poorly maintained fuel line and a failed cooling pump had caused fires aboard small vessels over the past 20 years. But the safety panel also concluded that a lack of preventive maintenance and fire training for crew members had contributed to the blazes.

Read the full story on LATimes.com.