Two crashes involving seven vehicles spilled oil and caused long delays in the morning rush hour.
A bus was in the first crash, which sparked long delays.
Reports said a bus and car crashed at 7.23am on the westbound A31 near Ringwood.
Another crash involving five cars was reported shortly after.
A spokesperson for Hampshire and Isle of Wight Constabulary said: "This was reported at 7.29am and involved five cars.
"No injuries were sustained.
"A lane was partially closed but has since been reopened."
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Despite the lack of injuries, the crashes caused significant disruption during the morning commute.
Drivers said they saw about six ambulances heading to the scene as traffic updates warned of major congestion.
National Highways said delays hit up to 30 minutes in both directions between the M27 and the A338.
Hampshire police confirmed that National Highways were dealing with an oil spill on the road following the bus collision.
Police said no injuries were sustained in the earlier collision involving a car and a bus.
