Are fireworks a health hazard?

It’s a question that has no doubt occurred to many as they’ve watched fireworks fill the sky with their magical light: Are there environmental and health effects from having so many rockets bursting in air?

Even in an era when seemingly every other summer weekend is cause for some kind of public or private fireworks celebration, many over lakes and ponds, we still don’t know for certain. But there is cause for concern. After all, the so-called color emitters that produce the dazzling hues are often metal salts or oxides or exotic compounds. The greens are usually from barium, the reds from strontium carbonate or lithium salts, the blues from copper chlorides, the whites from aluminum, magnesium, or titanium. Then there are the oxidizers to accelerate the burning of the color emitters, and the gunpowder often used to propel the rocket aloft and blow it apart. Some of those substances can have serious health effects.

“It is a really good question, and it is coming up more and more because we seem to be getting more liberal about the private use of fireworks,” says James Haney, a professor of biological sciences at the University of New Hampshire. “Since many of these are relatively rare, they haven’t been studied a great deal in fresh water.”

The Granite State, which boasts almost 1,000 bodies of water over 10 acres, from large majestic lakes like Squam and Winnipesaukee, to overgrown puddles like Sebbins Pond, has sounded some cautionary notes on the subject.

“The gases from the rocket and the explosion are released into the atmosphere, where they are inhaled by humans and animals, and hurt the ozone layer,” Jody Connor, then director of Limnology at the New Hampshire Department of Environmental Services, wrote in 2008. “In addition to the gases, the debris and burning metals fall back to earth where they litter the area, contaminate aquatic ecosystems, and poison the wildlife, eventually working their way up the food chain.”

In the United States, the fireworks fallout focus has been mainly on perchlorate, a chemical compound that provides the oxygen necessary for burning. Perchlorate, which can hamper the functioning of the thyroid gland, is a particular health risk for pregnant women and children. It is also considered a likely carcinogen. Some fireworks manufacturers have moved away from its use, though fireworks without it are generally more expensive.

According to a 2006 Massachusetts Department of Environmental Protection report, perchlorate, estimated to be 40 percent of the content of all fireworks, produces “particulate/debris fallout . . . that uniformly descends to the ground over a ‘football field’ size area of 3,600 square meters.”

So is enough being released to cause real harm?

That’s where uncertainty sets in. In 2007, the Massachusetts DEP concluded that the decade-long use of part of the University of Massachusetts Dartmouth as a fireworks launching site was the likely cause of perchlorate contaminaton in nearby soil and groundwater. DEP has also found significant levels in nine municipal water supplies, with fireworks the suspected cause in three.

Given both the current concerns and the larger uncertainty, we need more research. And in a region like ours, which is chockablock with universities and lakes, that’s a task awaiting a team of willing scientists.