RADNOR, Pa. (

TheStreet

) --

Airgas

(ARG)

rejected a $5.1 billion unsolicited takeover offer from

Air Products

(APD) - Get Report

, saying the bid "very significantly undervalues" Airgas.

Air Products

TheStreet Recommends

made the $60 offer

to buy rival Airgas last Friday after previous overtures were rejected. It also would assume about $1.9 billion in debt.

Shares of Airgas closed Tuesday at $61.35.

In a letter to Air Products CEO John McGlade, Airgas Tuesday said its "extremely enthusiastic about our company's prospects and are confident of achieving stockholder returns well in excess of what can be derived from Air Products' unsolicited and opportunistic proposal."

A merger of the two companies would create the largest industrial gas company in North America and one of the largest in the world.

Air Products previously has said it was ready to go hostile with the offer and take its offer directly to Airgas shareholders.

-- Reported by Joseph Woelfel in New York.

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