At least 15 people have checked into the hospital after breathing in black smoke from a chemical plant explosion in Crosby, Texas, on Wednesday. But because of a lack of environmental regulation, they might not know exactly what they’ve inhaled.

The plant — one of global chemical giant Arkema’s facilities that stores organic peroxides used to make plastics, rubbers, and explosives — flooded as Hurricane Harvey dumped trillions of gallons of rain across Texas. The water knocked out the backup power keeping the volatile chemicals cool, which later caused an explosion sending up thick plumes of black smoke.

The city evacuated people within a 1.5-mile radius around the plant in preparation, but law enforcement didn’t have the luxury of staying away. As of Thursday morning, 15 police officers had checked into a local hospital after spending time near the site. And unfortunately, they didn’t have documents to tell doctors what chemicals they may have inhaled. Instead, the hospital had to rely on statements from Arkema.

That’s because plants in Texas aren’t required to tell the public what chemicals they work with. In 2014, following an explosion at a fertilizer plant in West Texas that killed 15 people, Texas’ then-attorney general and now Gov. Greg Abbott decided that facilities wouldn’t have to disclose the chemicals they use to the public anymore.

In fact, Abbott famously told Texans that if they wanted to know what was in a plant, they could simply drive around and “ask every facility if they have chemicals or not.” While changing the rule didn’t cause much of a stir, chemical explosions and releases are more common in the U.S. than people realize — between 2004 and 2013, over 1,500 were reported.

“A lot of this information is kept [private] in the name of national security or trade secret information — not giving information to companies’ competitors,” said Kelly Harragan, the director of the environmental law clinic at the University of Texas at Austin. “But I think you know that line has gotten pushed too far, and the public needs to have access to this kind of information when it can affect their health and safety.”

Even now, Arkema’s CEO reportedly refuses to release an official document that would outline with complete certainty everything that’s in the Crosby plant. And that’s all legal. What Texas has managed to do, in essence, is turn “nondisclosure” into a form of compliance. And no government records, or ones verified by a third party, are available to the public. Arkema did not immediately respond to VICE News’ request for comment.

Because Arkema stores its chemicals at multiple locations throughout the facility, the company warned that more explosions could happen. The wind from Harvey — the worst natural disaster in the state’s history — could also shift, pushing the smoke outside the evacuated 1.5-mile area. The original risk management plan for the plant suggested 1.1 million people could be affected in a “worst-case” scenario.

In January, the Obama administration had tried to remedy the lack of publicly available information with an amendment to the EPA’s Risk Management Plan that required facilities to release information about the chemicals they store to the communities around them and offer training to first responders.

A few weeks later, however, when President Trump took over the White House, lobbying groups like the American Chemical Council — of which Arkema is a member — and the American Petroleum Institute saw an opening.

The groups requested that Trump use the Congressional Review Act to delay implementing the amendments to the EPA’s plan that covered accidental chemical releases. And Trump said yes.

The lack of publicly available information isn’t just worrisome because of the Crosby plant. According to a study by Texas A&M, over 2,000 facilities in the Greater Houston area store chemical compounds. While these facilities might not store chemicals as explosive as Arkema’s, there’s no way for the public to know.