The incident happened in the closing stages of the match, shortly after Fabian Orellana had given the visitors the lead at El Madrigal, and halted play for almost 25 minutes.
Villarreal are now set to be punished following a recommendation from Spain's Anti-Violence Commission (CSD).
A statement from the CSD read: "(The Commission) has agreed to propose a fine of 4,000 euros to Villarreal CF SAD and expresses its strongest condemnation against the events at El Madrigal on Saturday 15 February when, during the match Villarreal CF SAD v Real Club Celta de Vigo SAD, an individual - not yet identified - launched a tear smoke canister on to the field of play that produced a thick cloud of white smoke in the stadium.
"This fact caused the temporary suspension of the match and the evacuation for security reasons of all the spectators who were inside the sports arena.
"(The Commission) reminds football clubs they should make use of all measures to control the access of spectators into their stadiums to avoid events like those witnessed at Villarreal happening again at a sporting spectacle.”
The Commission also praised the work of security personnel at the stadium following the swift evacuation.
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