It’s a new day for the environment, and not in a hopeful sense.

A steel company’s request to Indiana authorities for “confidential treatment” when it dumped toxic metal into Lake Michigan last month is a worrisome sign that under the Trump administration we will be told less and less about threats to our environment.

Everyone, from environmental activists to ordinary Chicagoans who care about the safety of their drinking water, had better become much more vigilant.

The request came from U.S. Steel in an Oct. 31 letter to the Indiana Department of Environmental Management after chromium leaked on Oct. 25 from a company facility on the shore of Lake Michigan. Just six months earlier, a similar leak from the same plant fouled a river tributary that feeds into the lake.

The request for secrecy — to keep you in the dark — apparently worked. A Chicago Tribune review of online press releases shows that neither state officials nor the U.S. Environmental Protection Agency informed the public about the potentially hazardous leak.

The critical importance of leveling with the public in such matters also is illustrated by a new Better Government Association review and Associated Press investigative report of leaks from local nuclear power plants. The BGA and AP learned that radioactive material continues to leak from Exelon’s Illinois nuclear power plants. The leaks were properly reported, but we now are confronted by an EPA boss, Scott Pruitt, who takes a skeptical view of environment protections. We have less confidence that Pruitt’s EPA will partner with the public, and not with the despoilers of the environment, when such leaks occur.

According to the BGA report, radioactive waste continues to leak from the nuclear power plants more than a decade after chronic leaks led to a $1.2 million government settlement and the company promised to guard against future accidents. Exelon says the amounts were too little to be a health risk, but the leaks remind us our air and water can quickly become tainted to the point of hazard. We need both industry and authorities to be in the vanguard of protecting the environment.

Clearly, we all deserve to know promptly whenever there is a leak of toxic industrial substances that could endanger public health. In the case of U.S. Steel’s recent leak of chromium, the Halloween Day letter surfaced only because it was seen by law students from the University of Chicago who were tracking pollution violations. If data about the leak had been released promptly, independent scientists could have assessed it and made recommendations. That is how the public is protected.

Why didn’t U.S. Steel or the Indiana Department of Environmental Management, an agency considered lax by environmentalists, inform the public? Why didn’t U.S. Steel report the leak to the National Response Center, which keeps local officials posted about spills and leaks? Embarrassment is not a sufficient reason for secrecy.

Howard A. Learner, president and executive director of the Environmental Law & Policy Center, said the handling of the U.S. Steel leak is a sign that the EPA under Pruitt is signaling to companies that it is indifferent to such environmental threats.

“The message coming from Pruitt is to lay off industry,” Learner said. “The EPA is supposed to play the role of watchdog, or the cop on the block, that leads people to be more careful.”

We pay for cops to deter crime in our city, and we pay federal inspectors and scientists to keep monitor spills and leaks that might endanger our health.

When it comes to our environment, the Trump administration is sending ominous signals.