Back-to-back explosions at chemical plants only miles apart along the Mississippi River have given pause to those who live in the shadows of America’s dirtiest industries.

On Thursday, an explosion at a chemical plant in Geismar, La., owned by Williams Cos. Inc. led to two deaths and injuries – some serious – to dozens of others. Then late Friday, another explosion at a chemical plant just a few miles away in Donaldsonville claimed one life and injured eight people after a nitrogen tank exploded during an offload.

"The incident involved the rupture of an inert nitrogen vessel during the off-loading of nitrogen," a news release from the company, CF Industries, said. "There was no fire or chemical release nor is there any threat or hazard posed to the community."

Hundreds of industrial plants, many that either produce or consume poisonous and explosive chemicals, line rivers and bayous throughout the South, but in few places as heavily as around New Orleans and the Mississippi River.

Some 311 chemical manufacturers employing 15,727 people currently exist in the parishes that line the Mississippi from Baton Rouge to its mouth. That number excludes the large numbers of oil refineries and plastics manufacturers in the area.

To be sure, locals welcome jobs that pay an average of more than $40,000 a year. But explosions like the ones that roiled the river this week remind many of the dangers, both to human life and the environment, such jobs bring.

The explosions this week are “an example of what it's like to live along a massive petrochemical corridor," Marylee Orr, executive director of the Baton Rouge-based Louisiana Environmental Action Network, told the Associated Press. "It poses a risk to the workers first and then to the community that lives right along the front line."

The explosions also highlight a toxic paradox of one of America’s few examples of economic boom as low natural gas prices and welcoming state regulations spur development in areas already dominated by industrial activity.

The Mississippi River’s span between New Orleans and Baton Rouge – where the twin explosions occurred Thursday and Friday – is one example. The other is the petro-corridors hugging the Gulf Coast south of Houston.

Louisiana alone has welcomed more than $30 billion in industrial investment in the last two years. The state’s unemployment rate is 6.5 percent, a full percentage point lower than the 7.5 percent national average.

Some critics say Southerners and Republican leadership in many of the affected states have only themselves to blame for welcoming what some call “dirty industries.” But it’s also true that the US economy would likely struggle without such industries, and that the sacrifices by Southern states to take on potentially dangerous plants benefits the US as a whole.

Moreover, chemical plants are actually safer than the average industry, reporting a fatality rate of 1.9 workers per 100,000 compared to the national average of about 3 fatalities per 100,000 workers. The industry had 25 fatalities across the country in 2011.

Yet as incidents ranging from the Deepwater Horizon disaster in 2010 to the explosion at a fertilizer plant in the small town of West, Texas earlier this year, make clear, such accidents have the potential to wreak broader havoc, beyond loss of life. Many Americans are taking notice, especially since some studies have shown that one in three Americans are vulnerable to exposure to a chemical explosion or major release of toxins.

“When polled, over 70 percent of the population thinks we need better regulation of toxic chemicals,” John Deans and Richard Moore wrote last year in The Nation magazine. “National security experts have said for at least a decade that these ‘pre-positioned weapons of mass destruction’ are a weak link in our critical infrastructure. Workers in dangerous facilities want a safer place to work. Communities on train and truck routes to and from these facilities want to be safe, as do communities near the plants themselves.”

In large part because of the economic benefits, as well as the relatively safe working conditions, many Louisianans take a live-and-let-live attitude toward the looming petro-plants that form imposing rural skylines.

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"For the most part, day to day, month to month, year to year, you don't really think about” the dangers, Ascension Parish Councilman Travis Turner told the Associated Press. "Everybody knows somebody – a brother or cousin or uncle – who works at a plant. When something happened, everybody is worried about the worst case scenario, like” the recent explosions.

The US Labor Department's Occupational Safety and Health Administration is investigating both explosions. So far, there’s no evidence of foul play or terrorism in either blast, police authorities say.