By the numbers: As of noon on Thursday, the North Carolina Department of Environmental Quality said 30 swine lagoons have overtopped, a number that more than doubled since Tuesday.

• At least 132 hog lagoons are at risk and the number has continued to rise, according to data issued Thursday.
• Six hog lagoons had suffered structural damage, another 40 have are at the brim, meaning overtopping is likely.
• About 3.4 million chickens and turkeys and 5,500 hogs have been killed in flooding from Florence as rising North Carolina rivers swamped dozens of farm buildings where the animals were being raised for market, according to state officials.

Threat level: The lagoons, dug into the earth next to pig housing, are where the state’s more than 2,000 industrial-sized hog farms pump animal waste, which is then treated with waste-eating bacteria. The bacteria give lagoons a distinctive pink color.

• Studies have shown hog lagoons, sometimes called concentrated feeding operations, can cause health problems for those who neighbor them naturally due to how they carry pathogens and unsafe chemicals.
• The lagoons also have a large amount of nitrates, which can cause algae blooms that deprive fish of oxygen.
• Also, excess nitrates that seep into water supplies can cause "blue baby syndrome," when nitrogen obstructs red blood cells' abilities to carry enough oxygen, causing a baby's skin to turn blue, according to the New York Times.

Reality check: The North Carolina Department of Environmental Quality said it has limited resources in testing the harm the flooding is doing in real time, as flooding from all waterways "could last weeks," per a previous Axios report.

Go deeper: The ties between Hurricane Florence and climate change