Chemical plants and oil refineries spewed millions of pounds of toxic chemicals into the air and on the ground after Hurricane Harvey struck Texas a year ago. Some parts of the state did a better job than others in controlling those emissions and spills, according to a new report that tries to take lessons from Harvey to better prepare for the next storm.

The analysis, from the Environmental Integrity Project, looks at mandatory pollution reports companies filed. It found that something went wrong when it came to the monitoring and managing of toxic emissions during Harvey.

Here are some of the findings.

Many petrochemical plants waited too long before they shut down.

In preparation for the storm, oil refineries in Corpus Christi shut down before Harvey made landfall. That was the right call, according to the report. It probably helped Corpus Christi avoid a situation like what happened in Houston, where plants didn't shut down the storm hit.

"Many of those [in Houston] were emergency shutdowns and that always comes with more pollution," says Ilan Levin, who directs the Environmental Integrity Project in Texas.

In other cases, facilities in and around Houston were damaged or even destroyed, causing greater harm to the environment and public health.

The report urges preemptive, better-coordinated closures at vulnerable plants to stop this from happening.

Officials should have better communicated the danger of toxic emissions.

Harvey caused at least 8.3 million pounds of unpermitted air pollution from petrochemical plants, much of it dangerous to humans. But officials frequently downplayed the risk of those emissions and offered "broad assertions that the air quality was not a danger," says Bakeyah Nelson, executive director of Air Alliance Houston.

The report finds that officials should better monitor and communicate the risk of air pollution.

"At a minimum, a disaster-based air-quality-monitoring plan should be developed to monitor the air near communities that are closest to these facilities," Nelson says. "Facilities within close proximity to residents should be held to a higher reporting standard."

Facilities need to develop safer storage for dangerous chemicals.

At least 400 storage tanks for gasoline and other petrochemicals in the Houston area have what are called floating roofs, "where the top of the tank floats on the liquid itself," Levin says.