Cordon is in place while chemical is identified. Ambulance staff are treating nine people.
M6 closed in both directions between J3 A444 / B4113 (Nuneaton / Bedworth / Coventry) and J4 M42 / A446 (Coleshill), congestion on M6 to J2 M69 / A46 (Coventry) Northbound.
More top news
The Olympic swimmer is up against two other athletes for the British Swimming award.
Police have released CCTV of the moment the man was hit in a bid to prompt the driver to come forward
Callum Howkins was on holiday in Mauritius with his family when he died while swimming with dolphins in 2014.