Firefighters were among a group of people treated at the scene of a chemical tanker fire that closed the M6, north of Coventry.
Emergency services said 10 people, including the lorry driver and eight firefighters, were taken to hospital as a precaution after the tanker caught fire at about 9.40am.
One person remained in hospital, authorities said.
A section of the motorway was closed in both directions and motorists experienced long delays, the Highways Agency said .
Some drivers caught up in the traffic queue behind the accident were evacuated from their cars after firefighters put in a 1km exclusion zone.
The ambulance services said more than 100 people were taken to a nearby service station to undergo checks, while local residents were advised to shut their windows.
Warwickshire Police said the drama happened after a tyre blew out and caught fire.
Andrew Hawley, who was at the scene, said on Twitter that the situation was "a nightmare".
Five ambulances were sent to the scene, as well as a rapid response vehicle, paramedics and specialist hazardous area response teams.
The motorway was reopened late on Wednesday evening.
A Highways Agency spokesman said: "The M6 southbound fully reopened between junctions 4 and 3 at around 7.45pm, with the M6 northbound between junctions 3 and 3a fully reopening at 10pm.
"A small section (about 40 metres) of the hard shoulder on the M6 northbound, between junctions 3 and 3a, was damaged and will remain coned off until it can be resurfaced."