China is responsible for a dangerous spike in atmospheric levels of CFC-11, a chemical outlawed for its destructive impact on Earth’s ozone layer, according to an exhaustive report released Monday by the UK-based Environmental Investigation Agency (EIA).

“CFC-11 is used as a foam blowing agent for the manufacture of molded foam panels and spray foam used for insulation purposes,” EIA’s report reads. “EIA has evidence from 18 companies in ten provinces that they use CFC-11. Detailed discussions with company executives make clear that these are not isolated incidents but instead represent common practice across the industry.”

The report compiled statements from 21 Chinese foam insulation manufacturers, most of which confirmed that they were producing the banned chemical for quality and cost reasons.

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“You had a choice: Choose the cheaper foam agent that’s not so good for the environment, or the expensive one that’s better for the environment,” Zhang Wenbo, owner of a refrigerator factory in Xingfu, Shandong Province, told the New York Times. “Of course, we chose the cheaper foam agent. That’s how we survived.”

“They never told us until last year that it was damaging the atmosphere,” Zhang said. “Nobody came to check what we were using, so we thought it was OK.”

The ozone layer, a film of trioxygen gas that envelops our planet, shields life on Earth from the devastating effects of the Sun’s ultraviolet radiation. Its essential role in human health and environmental safety was internationally validated by the 1987 Montreal Protocol on Substances that Deplete the Ozone Layer, a treaty that phased out the use of substances—particularly chlorofluorocarbons (CFCs)—that damage this protective screen.

The Montreal Protocol has been hailed as one of the greatest environmental success stories in history. But now that progress has been threatened by the lax attitude of China’s construction industry toward global environmental regulations.

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