A corporate culture of ask no questions lies at the heart of a scandal in which Hino Motors Ltd. falsified environmental performance data of commercial vehicles over many years, according to a third-party report.

The report traced the problem to an executive demanding improved fuel efficiency in the final stages of product development.

Managers readily reassured the individual they could achieve the goals, ignoring the company’s technical levels and development schedule, and passed on the work burden to subordinates.

Employees in charge tampered with performance test instruments to falsify data in line with the goals set by higher-ups.

This is a pattern that emerged in explaining the scale of the company’s misreported fuel economy and exhaust gas emissions data of a wide range of models over many years, according to the report by a panel investigating the scandal.

The company’s culture, which discouraged employees from questioning superiors, led to its betrayal of values taken as a given by society.

We urge Hino and its parent company, Toyota Motor Corp., to undertake a sweeping review of the truck maker’s corporate governance.

Hino falsified performance test data for the transport ministry’s “type certification,” which applies to a specific model’s overall compliance with the standards required for sale.

In the report published last week by the outside experts, it became clear the company has been engaged in fraudulent business practices since at least 2003.

The report said the section responsible for product development and performance tests faked data on its own without informing other sections of the way it was doing business.

The fraudulent practice over fuel economy started after an executive insisted on achieving standards required to make large commercial vehicles eligible for tax incentives.

Since the overstated specifications were used for the development of subsequent models, the section repeatedly fabricated related data every time the company applied for “type certification.”

The company also lied outright to the transport ministry in 2016 when it stated it was not involved in data falsification during the ministry’s inspections of automakers for such irregularities.

The inspections were carried out in the aftermath of revelations that Mitsubishi Motors Corp. faked fuel economy data. Hino is guilty of egregious deception.

In describing the background to the scandal, the report pointed to Hino’s “top-down” culture, which even resulted in harassment of employees by superiors.

It also cited a deep gap in perception between the management and rank-and-file workers about the company’s capabilities.

Hino’s current and past executives, even if they were not directly involved in the fraud, should be held responsible for allowing such an unhealthy corporate culture to remain unchanged for so long.

What is especially notable is the fact that the falsification concerned the “green” credentials of vehicles.

The report noted that environmental performance is now a crucial factor for automobiles to be embraced in today's social environment.

But this recognition was apparently not widely or strongly shared within the company, the report said.

Under its “Hino Environmental Challenge 2050” project, Hino has pledged to reduce its environmental footprint to a minimum.

The lofty slogan sounds hollow if it is not supported by technological and management prowess.

Hino President Satoshi Ogiso acknowledged during a news conference that the management bore grave responsibility for the scandal.

“We will take strict disciplinary actions after determining who should be held responsible,” he said.

Ogiso should be aware that it will be a formidable challenge to regain public trust.

Toyota, which made Hino a subsidiary in 2001 and provided many of the company’s successive presidents, deserves some of the blame.

Toyota should recognize the scandal as a failure of its group management.

Although the “type certification” system is based on the notion that automakers will conduct business with integrity, the transport ministry needs to seriously reflect on the fact that it failed to detect misconduct on a massive scale over many years.

We urge the ministry to act swiftly to review its approaches to inspections and supervision.

--The Asahi Shimbun, Aug. 12