阻燃剂是否是对抗森林火灾的最好办法？

U.S. officials are testing a new chemical mixture that is able to slow down the progress of wildfires.

But critics say the Forest Service should be spending less on these mixtures known as fire retardants and more on firefighters.

The effects of drought

Much of the American West is facing a drought — a long amount of time with very little rain.

The National Interagency Fire Center in Boise, Idaho, reports that so far this year there have been more than 31,000 wildfires. Those fires have burned about 13,000 square kilometers.

That number is well above the 10-year average for the same period of about 24,000 wildfires and 5,000 square kilometers burned.

Wildfire seasons have become longer as the West has become warmer and drier in the past 30 years.

In 2020, The Forest Service used more than 190 million liters of retardant for the first time. It used over 190 million liters again last year to fight some of the largest and longest wildfires ever recorded in California and other states. The fire retardant cost those two years reached nearly $200 million.

In comparison, over the previous 10 years, the agency used 115 million liters each year.

The U.S. Forest Service said tests started last summer are continuing this summer with a magnesium-chloride-based retardant from the company Fortress.

Fortress says its retardants are effective and better for the environment than other products. Another company, Perimeter Solutions, says its ammonium-phosphate-based retardants are better.

The main ingredient in Fortress products, magnesium chloride, is taken from the Great Salt Lake in Utah. This method and process is more environmentally friendly than mining and processing phosphate, the company says. The Forest Service last summer tested the company's FR-100, and this summer said it will test a version called FR-200.

Perimeter Solutions, which has buildings and equipment throughout the American West, has had a number of name and ownership changes over the years. Still, it has been the market leader for more than 20 years. The company's Phos-Chek LC-95A is the world's most used fire retardant. The company is moving to a new retardant called Phos-Chek LCE20-Fx. The company said it is made out of food-grade substances, making it a cleaner product.

Criticism from environmentalists

But two noNPRofit groups say both kinds of retardant harm the environment. The groups suggest that the U.S. Forest Service should be spending less on fire retardant and more on firefighters.

Andy Stahl leads Forest Service Employees for Environmental Ethics, and Timothy Ingalsbee leads Firefighters United for Safety, Ethics, and Ecology. Both said that the ammonium-phosphates-based retardant is a fertilizer that can help invasive plants. They believe it might be responsible for some algae blooms in lakes.

Stahl and Ingalsbee said the magnesium-chloride-based retardant is a salt that will limit plant growth where it falls, possibly harming threatened species.

Both are concerned that either one of the chemicals will be dropped directly on waterways. They are worried about the possible harm the retardants could cause to aquatic species.

I'm John Russell.

Keith Ridler reported on this story for the Associated Press. John Russell adapted it for VOA Learning English.

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wildfire – n. a fire in a wild area (such as a forest) that is not controlled and that can burn a large area very quickly

algae bloom – n. a fast and large increase in algae - simple plants that have no leaves or stems and that grow in or near water

aquatic – adj. living or found in or near water

species – n. biology : a group of animals or plants that are similar and can produce young animals or plants : a group of related animals or plants that is smaller than a genus