Along most of its coastline, in its bays and estuaries, and in many of its rivers and lakes, America is under mounting attack by another enemy of its own making — toxic green algae. It’s like a bad horror movie, with the slime sprawling across vast reaches of water (so much that it’s visible from space), eventually covering beaches and burping a neurotoxin that is deadly to earthlings. As a movie, it wouldn’t get past a concept lunch in Hollywood today (Hey, Arnie! It’s been done, okay?) but it is raising real dread — not the fake movie kind — from California to Florida, from the coast of Washington to the coast of Ohio. Yes, Ohio.

First let’s be clear about the primary cause of algae blooms. It is the excessive and incautious use of fertilizer by industrial agriculture, compounded by the excessive erosion that results from industrial practices. The Big Ag lobby has browbeaten almost everybody into mentioning, when they talk about algae blooms, the contribution of city lawns, insufficient sewage treatment and storm runoff. But the size and extent of the blooms, nationwide, tracks over many years with the increasing “consumption” of fertilizer. Actually, if it was consumed, by the plants it is intended for, there would be no problem. But when too much is applied, or it’s applied at the wrong time of year, it washes off, and is consumed by algae instead.

Garden variety algae is one kind of problem. Toxic algae is another. Generally, algae turns toxic — begins to emit a deadly neurotoxin — when three things happen to an algae bloom. It gets very large, very warm, and is infused with an extra-large amount of nutrients. Once upon a time those things didn’t happen very often. Now they do. Everywhere.

Along California’s Central Coast, dozens of beached, convulsing sea lions, many of which die, are being seen every day. Pelicans, having scooped up a beakful of contaminated fish, are falling dead from the sky. Many fisheries have been closed since April, when high levels of toxin were first detected — this year. “These blooms are getting more frequent and larger every year and affecting more and more animals,” according to Shawn Johnson, director of veterinary science at The Marine Mammal Center in Sausalito.

Ahalf million residents of Toledo, Ohio were told not to even touch their tap water for two days this month after an algal toxin was discovered to be present. An algae bloom had occurred near the city’s water intake in Lake Erie, miles from the shore. Officials sounded the all clear two days later, even though the algae bloom is still there. Algae typically cover enough of Lake Erie in recent years to be clearly visible from space.

Just off the west coast of Florida. the biggest red tide in ten years stretches over 4000 square miles of the Gulf of Mexico, to a depth of 100 feet. A red tide is just another color of algae bloom, and like the others when it gets big enough and warm enough it starts oozing poison. This one has killed fish by the tens of thousands, and as it comes ashore its colorless and odorless toxin threatens larger animals including humans.

The Chesapeake Bay this year has one of the largest dead zones on record. A dead zone is a volume of water stripped of its oxygen by decomposing algae, which has flourished because of an oversupply of nutrients. This year, the 34th successful year in the war on pollution in the Chesapeake, the dead zone comprises a cubic mile of water in which nothing can live.

The dead zone in the Gulf of Mexico at the mouth of the Mississippi River is also one of the largest this year, dwarfing the Chesapeake’s problem at 5,000 square miles.

This problem is not caused by climate change, although climate change makes it worse by providing the algae with warmer water for longer periods of the year. The cause of this problem and of climate change are the same: rampant pollution by industrial interests that governments cannot or will not restrain.

The much-touted efforts to “solve” the problem of agricultural runoff — you will see estimates that billions have been spent in the effort — consist mainly of puffery: signs that say “you are now polluting an important watershed” and resolutions about voluntary programs (“you could stop polluting this watershed if you wanted to.”)

Meanwhile the slime spreads, and dies, and spreads some more, killing when it’s alive and killing after it’s dead. Until the people who stimulate algae blooms start going to jail for it, the algae will continue to poison America. Don’t hold your breath.