He's heard that it's impossible, but Timothy J. Rohn swears human waste is raining from the sky.

"It doesn't look like friendly stuff," said the 47-year-old Richland Township resident whose home is in the flight path of airplanes going to and from MBS International Airport. "Bird poop is kind of white, but this is a lot of brown. It's a mess."

Tuesday, for the second time in as many months, Rohn found the suspicious substance splattered on the side of his truck and his home, on North Raucholz near Geddes.

"It's in the exact same spot," he said. "Some of it is white, but there are a lot of brown blotches, and it doesn't look like any goose poop to me. Plus, it would be quite a coincidence to have that many birds hit the exact same spot twice."

Even Richland Township Police Officer Gary Wade is perplexed.

"It's manure," Wade said, "and it came from the sky. If it came from some kind of fowl, it had to be one heck of a large flock. To me, it looks like bird droppings but, man, it had to be an awful large flock of birds. It's all over."

Both Rohn and Wade said they know that airplanes cannot discharge waste in flight because the mechanism that opens the hatch is accessible only from the outside of the craft.

Still, Rohn wonders if the holding tank or valve could leak.

"The airplanes turn when they go over our house, so they can line up with the radar on Orr," Rohn said. "What I'm wondering is whether there is a cap that can fall off or leak, because this is the second time it's happened, and I don't want it to happen a third time. What if my 8-year-old daughter was outside when it happened?"

Rohn said the substance definitely is excrement and, from what he could see Tuesday night, it may have contained toilet paper that had broken down in chemicals. He said he did not notice a blue or other chemical tint to the substance.

The material, which appeared between noon and 3 p.m., caused no permanent damage to Rohn's house or truck. The first time it happened, he let rain and snow do the washing for him.

Rohn said he plans to contact airport officials today, just to get more information.

"I was irate at first," he said. "But I took an aspirin and laid down and called it a day."