A highway that was slippery with de-icer sprayed by a state road crew was the site of three separate accidents Monday that sent two people to the hospital, according to a traffic investigator.

The three cars were traveling south on Highway 20 at approximately 2 p.m. when they started sliding as they hit the curve south of Arnold Road. One ended up in a nearby field, one went into a ditch and another rolled over.

Investigators are focusing on a substance sprayed on the highway earlier in the day.

“We’ve got to figure out what this substance is,” said Deputy Lane Campbell of the Island County Sheriff’s Office, speaking at the accident scene. “It wasn’t an issue for the northbound traffic but it was for the southbound traffic.”

It turned out that a de-icer sprayed on the road earlier in the day caused the slippery conditions on the road, Campbell said Tuesday morning following further investigation.

“We pretty much came to the conclusion that it was the de-icing material,” Campbell said.

He said that he didn’t know why the de-icer caused the slippery conditions and there weren’t any reports of similar situations on the highway.

The road was still slippery to walk on after it was closed.

The Washington State Department of Transportation sprayed de-icer on Highway 20 and Highway 525 Monday.

“It was a pretreatment which prevents ice or frost from forming on the highway for 72 hours,” said Ron Morton, assistant maintenance superintendent for the DOT. Work crews have used the product in the region for the past three years. The substance gets applied to highways when the temperature drops to freezing.

The de-icer is made from agricultural byproducts and is non-corrosive. The substance eventually dries on the roadway and reactivates when it comes into contact with water.

Morton said he didn’t know how long it takes for the de-icer to dry on the road because there are many factors impacting drying time.

Pat Moylan, DOT maintenance manager, said that the de-icer is environmentally friendly and is more effective than sanding the road after ice has formed.

Contrary to Campbell’s assessment, Moylan said people driving prudently on the highway shouldn’t be affected by the substance on the road.

“We wouldn’t be using it if it wasn’t a safe product,” Moylan said.

He added that employees checked application equipment when concerns about the de-icer arose, but that equipment was functioning correctly.

“I’m confident we’re applying it correctly,” Moylan said, adding there aren’t any plans to change how the product is applied.

Deputy Campbell said speed was not an issue with Monday’s accidents.

Several motorists lost control on southbound Highway 20 Monday afternoon south of the intersection with Arnold Road.

Shane Saunders, who lives in the Rolling Hills area south of Oak Harbor, said he was traveling south on Highway 20 heading to Coupeville when he ran into problems.

“I was just coming around the curve when the truck slid around,” Saunders, who was driving a Ford pickup, said. He tried to steer toward the ditch to avoid swerving into the oncoming lane. Instead he bounced from the ditch, through the lanes and into a nearby field and eventually stopped near the ditch parallel to the highway.

He said he was wearing a seatbelt, wasn’t injured and the major damage to his truck came when a rock struck his windshield.

Shortly thereafter, Oak Harbor resident Rosemary Magtira was driving a late-model Chevy Malibu which also started sliding on the highway and eventually ended up in a ditch.

One passerby, Freeland resident Scott Blatney, who was heading north to Oak Harbor, stopped to call 911 and to check on the accident victims.

While talking on the phone, he witnessed the third accident.

“I was on the phone with 911 when this one went,” Blatney said.

Oak Harbor resident Sally Elder was driving a Chevy Corsica and lost control of her car, rolled and came to rest in the ditch.

“It’s amazing that we didn’t have more (accidents),” Blatney said.

Marv Koorn, chief of North Whidbey Island Fire and Rescue, said it took about 15 minutes to pull Elder out of her car. Rescue crews had to remove the driver-side car door before pulling the woman from the vehicle.

Elder and Magtira sustained minor injuries. Elder was transported to Whidbey General Hospital while Magtira was transported to the Naval Hospital.

Highway 20 remained closed while investigators examined the scene. It also had to be closed until workers from the Department of Transportation could come out and sand the road. It was open by 4 p.m.

Traffic was detoured onto Arnold Road and Holbrook Road while the highway was closed.