The Football Association and Everton will both look into an incident where Richarlison threw a smoke flare back into the Goodison Park stands after his vital winner against Chelsea.
The forward scored on 46 minutes as relegation-threatened Everton won 1-0.
Richarlison celebrated before throwing the device - lobbed on to the pitch from the Gwladys Street End - into an area where there were no fans.
"We will look into the matter," Everton said.
"As far we we are concerned, Richarlison was attempting to throw it out of the ground."
In February, Liverpool midfielder Harvey Elliott was contacted by the Football Association after handling a red flare following the side's Carabao Cup victory at Wembley.
Pyrotechnics are banned from football stadiums in England.
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