I have never worked for a company that was dogmatic about project postmortems but I have always wished I had. After all, project postmortems teach us so much.

Learning from the mistakes and experiences of others constitutes the better part of our business education. It’s why we ask successful entrepreneurs to coffee and hang on every word when they speak at conferences. All those stories are postmortems. Postmortems condense all the experience and learning into a nugget of shared wisdom.

Despite their value, postmortems are uncommon. They exist only in delicate corporate cultures that demand excellence but support learning. Harder still, framing one’s own failure to colleagues daunts the entry-level employee as much a seasoned CEO.

It’s rare to find an enterprise that conducts postmortems consistently. Very few startups do. But I came across one business in a sector I wouldn’t have expected that exemplifies the value of the everyday post-mortem.

Alcoa, the Aluminum Company of America, generates $24 billion in revenue and for decades held the title of largest aluminum producer in the world. In the mid-1980s, the company hired Paul O’Neill as CEO. O’Neill changed the course of the business and doubled revenues in ten years because he instilled one particular value in the company. Unlike his predecessors who focused on increasing profitability to drive market cap, O’Neill championed safety as priority one from his very first shareholder meeting.

This ostensibly odd decision created a cascade of cultural changes within Alcoa. First, it united the interests of managers and unions who had been at odds over wages and benefits. After all both sought safer working environments for their teams. Second, because every accident needed to be reported in a timely fashion according to company policy, Alcoa became one of the first large enterprises to adopt email. Last, as employees focused on reporting accidents quickly and widely, the company cultivated a culture wherein people learned from others’ mistakes and everyone benefitted as a result. Accident rates plummeted, productivity rose and the business boomed.

A few years into O’Neill’s term, at a shareholder meeting, a Mexican nun (who was a shareholder of Alcoa) pointed out to the CEO that some members of her parish had suffered exposure to toxic gases working for Alcoa. The company investigated. They discovered that one of the most senior and tenured members of the management team, Bob Barton, had covered up the gas leak. O’Neill fired Barton immediately.

O’Neill said later, “…no one else had the opportunity to learn [from the accident]. Not sharing an opportunity to learn is a cardinal sin.” And his employees agreed.

Postmortems demand a culture of honesty and communication, two of the core values of the strongest relationships and cultures. I hope we see more of them in startups.