A towing company in business in the Des Moines area for 88 years had not lost an employee to a crash until Tuesday evening, when two company drivers — and two over-the-road truck drivers — were killed in the same accident on Interstate Highway 80.

The cause of a crash that killed the four men in Poweshiek County, about 50 miles east of Des Moines, remains unknown, authorities said Wednesday. Towing industry workers said the accident highlighted the need for drivers to pay attention and, when they see people working on the shoulder, get over, as state law requires.

Hanifen Towing drivers Jesse J. Inman, 29, of Ankeny and Daniel Walsh, 60, of Des Moines died while trying to help an Illinois man whose semitrailer had broken down. Another truck crashed into the vehicles, killing its driver and the other three men.

Inman leaves behind a wife and three young children, one 6 weeks old. Collin Allen, a manager with Hanifen Towing, said Inman had been with the company about six years.

"He loved his family. He loved the outdoors and he was looking forward to duck-hunting season," Allen said.

Walsh had worked at the towing company for decades.

"Their daughter just had their first grandbaby out in Indiana," Allen said. "He was such a big-hearted guy. He got a lot of compliments from our customers because he liked to go out of his way for people."

Julie Hanifen, co-owner of the company, said she is waiting like everyone else to find out what happened.

Hanifen said that in the 88 years that the company has been in existence in the Des Moines area no employee had been killed on the job until Tuesday.

Allen and Hanifen said towing is dangerous work.

"It's hard to prevent what the other guy is going to do," Hanifen said.

This much is known about the crash, according to the Iowa State Patrol:

The semitrailer driven by James Langholf, 50, of Dakota, Ill., broke down on the westbound lanes of the interstate, at about mile marker 188 southeast of Grinnell, and pulled off onto the shoulder.

Inman and Walsh were called to help out. They parked their tow trucks near Langholf's truck, with one tow vehicle on each end of it.

About 7 p.m., a truck driven by Herbert Arthur Terrell, 54, of Huntington, Ind., sideswiped one tow truck, then struck the parked semitrailer, pushing it into the other tow truck, troopers said.

All four men were dead at the scene. The cab of Terrell's truck was damaged. He had to be pried out of the wreckage.

Terrell was heading west into a setting sun when the crash occurred. Sunset on Tuesday was 7:28 p.m. Law enforcement agencies have been warning of sun blinding drivers this time of year as it now is lining up with east-west roads. The same is true for the rising sun in the east in the morning.

However, State Patrol Lt. Randy Jones said there was no indication the sun or anything else played a part in the crash. Traffic investigators continue looking for answers.

Langholf was driving for Howe trucking company. Terrell was working for Hiner trucking company.

A.J. Forneris of Perry's Service and Towing in Des Moines said area tow truck drivers were buzzing about the accident Wednesday.

"The most dangerous thing in the world is to be working along the highway, especially the interstate," Forneris said. "We all take precautions. But you would have to have three eyes in your head to be safe.

"We have a move-over law in Iowa, but not everyone is obeying it," Forneris said. "Drivers of cars and trucks and SUVs and vans are moving over. They seem to know about the law. Semi drivers are not obeying the law."

Forneris said several tow drivers he knows were complaining Wednesday about semi drivers not moving over.

Rob Abbott, vice president of safety policy with the American Trucking Associations, said one thing that would help is uniform national rules governing large trucks that would prevent confusion for cross-country drivers.

Iowa's move-over law took effect in the summer of 2002. It says that a driver approaching a stationary authorized vehicle that is displaying flashing lights shall make a lane change or slow down if changing lanes is not possible.

The law also applies to operators of a motor vehicle approaching a stationary towing or recovery vehicle, or a stationary highway maintenance vehicle displaying flashing .

Brenda Neville, president of the Iowa Motor Truck Association and Towing and Recovery Professionals of Iowa, said: "This tragic accident is an opportunity for us as motorists to always remember to exercise great caution when a tow truck is on the side of the road."