The general manager of Chevron's Richmond refinery says his firm wants to earn back the community's trust in the wake of last year's devastating inferno that nearly killed 19 workers, sent 15,000 people seeking medical attention and hospitalized about 20.

That public healing process cannot begin until the company fully acknowledges its culpability and complete cultural and systemic breakdowns. Its own internal analysis essentially blames the pipe failure that caused the fire on poor documentation and miscommunication. That won't cut it.

The U.S. Chemical Safety Board's new investigation report paints a very different picture. It describes a company that failed to make essential repairs despite more than a decade of alerts from its own staff and longtime, industrywide recognition of the potential danger.

The board found that Chevron's in-house experts warned repeatedly of sulfur-caused corrosion, the cause of the pipe failure. The phenomenon was first observed in the late 1800s and the refinery industry has been aware of the problem in low-silicon carbon steel pipes since 1974.

Chevron's own metallurgical manual warns of the "insidious" nature of the problem because the corrosion can spread over large sections of pipe, causing big ruptures rather than just pinhole releases. Chevron facilities had experienced eight sulfidation corrosion incidents since 1988 -- including a 2007 fire at the Richmond refinery.

In 2002, significant corrosion was found in the pipe that eventually failed. In 2005 and 2011, upgrading of the pipe to a more corrosion-resistant metal was recommended. In 2003, 2006 and 2009, thorough testing was recommended. In 2006, 2007 and 2011, other parts of the line were upgraded. But the pipe that failed was not tested nor replaced.

"Chevron management denied multiple recommendations to replace the ... line," the safety board found.

Higher sulfur content and greater heat accelerate the corrosion process. Yet, over the years since the pipe was installed in 1976, Chevron turned more to non-domestic crude feed stock with higher sulfur content. It increased the temperature of the material flowing through the line.

And it removed equipment designed to reduce the amount of sulfur from the fluid -- yet failed to conduct the required analysis of how that might affect the corrosion rate of the pipe.

The safety board found that by last year, at the time of the fire, the pipe wall had thinned by about 90 percent. It was down to about half the thickness of a dime. On the evening of Aug. 6, it began to leak.

Rather than immediately shut down the unit, managers tried to devise a fix. What followed was 2½ hours of failed attempts to stop the leak as it grew larger. The pipe eventually ripped open. A hydrocarbon vapor cloud erupted into a wall of fire as workers barely escaped.

This tragedy was not merely the result of miscommunication. Chevron ignored decades of warnings. Going forward, the refinery must show continuing corrective action, full transparency and complete cooperation with oversight agencies.

It will take Chevron years to rebuild the community trust it violated. The time to start is now.