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AP) – Missouri senators are calling on Attorney General Chris Koster to investigate a recent spike in propane prices.

Sen. Mike Parson, of Bolivar, said Friday that companies are sending more propane overseas, leading to a shortage throughout the Midwest. He says the shortage causes prices to rise and gives big profits to corporations. He wants Koster to see if companies are price gouging.

The Missouri Propane Gas Association says the shortage is caused by more exports and increased demand due to colder weather and higher crop yields. Propane is used to dry crops after a harvest.

A spokeswoman for Koster had no immediate comment Friday. Parson says the attorney general’s office told him they would meet Monday to consider his request.