MCGREGOR, IOWA - McGregor is a cozy town wedged between soaring bluffs and the lazy curve of the Mississippi River in northeastern Iowa. The main drag is lined by tidy 19th-century brick buildings. Two lovely nature preserves, Pikes Peak State Park and the Yellow River State Forest, sit nearby.

On a sunny September morning, the streets were spotless and quiet.

For now.

It wasn't this way for much of the summer. Until a month ago, hundreds of trucks from a nearby frac sand mine roared through downtown, instead of going around the village that relies on tourism for survival. The trucks spewed clouds of sand and dust and shook the historic buildings so hard the walls of some cracked.

In June, a couple visiting from California for their 50th anniversary wrote a letter complimenting residents for their hospitality, but added:

"However, much to our dismay, we were greeted with huge trucks roaring through town 24 hours a day. The simple act of crossing the street became a safety hazard, and a normal night's sleep [was] impossible. We cannot emphasize enough the effect this has on our considering McGregor for future stays."

The local sand pit had been around for decades and was not a problem. Not until the sand became valuable for "hydrofracking," a fairly new process used to extract oil or natural gas from the ground.

At first, local officials were thrilled with the mine's expansion, as it would mean as many as 150 new jobs. They didn't realize, however, that the main street was a state highway, and the city had no control over it. So instead of going around town, the trucks barreled through downtown on their way to Wisconsin. Besides the noise and traffic, the town had a perpetual layer of sand dust, many residents said.

McGregor Mayor Gay Hallberg asked the owner of Pattison Sand, "Why are you doing this to us?"

According to Hallberg, he replied: "Because I can."

Pattison did not return a phone call asking for comment.

In several Minnesota counties the industry is set to explode. Critics of frac mining have already visited McGregor to see for themselves the potentially disastrous unintended consequences of the industry.

The trucks from Pattison stopped suddenly a month ago. City officials are not sure why, but think it may be because of a temporary glut of sand on the market. The truck drivers were laid off, an early indication of the boom-bust nature of mining. But rumors are they began rehiring them last week.

"It started up overnight," said Lynette Sander, the city administrator. "For all I know, it could start again tomorrow night."

That would not please Linda Boeke, who owns vintage clothing shops inside two historic buildings on Main Street. As she walked around the building showing cracks in the foundation, she talked about what life was like when the trucks are rolling.

"We put in air conditioners because we can't open our windows because of the dust and noise," she said. "We sleep in the back, but we can still hear the trucks and feel the building shake at night. I'm concerned about the infrastructure, that we'll have to replace the streets and sewers and we'll be stuck with the bill."

Her husband, Jim, has a nuanced view of the situation.

"It's not black-and-white," he said. "This country is in economic decline and we need the fuel. That guy does create jobs, and we need those."

The Boekes used to rent rooms to mine employees, and so have seen some benefits to the mine.

"It's a two-edged sword," he said.

It's a sentiment echoed around town.

"Truthfully, I like the jobs for the guys," said Hallberg. "I like them coming into [the store] where I work. But I want those trucks out of town."

Hallberg even petitioned the Iowa Department of Transportation for help. "They said their business is to move traffic, not stop it."

Hallberg said some residents have complained of respiratory problems since the sand trucks began. The town is in a narrow valley and sand gets trapped in the air.

"It looks almost like smoke," Hallberg said.

Hallberg and Sander said the issue has divided the community. People outspoken about the problems have had their jobs threatened, and because land is being bought up secretly, there is a lack of trust between neighbors.

Asked what advice she would give Minnesotans as they consider sand mines in their neighborhood, Hallberg said: "Research. Ask a lot of questions. Talk to experts."

"Be prepared," said Sander. "Don't just look at the jobs, look at the impact on the town and the county. The pros are great, but there are a lot of cons we didn't know about."

"Tourism and sand? I don't think it's a good mix," she said. • 612-673-1702