Fertilizer producer K+S sued Dow Chemical's Rohm & Haas unit, saying that it paid the company too much for its Morton Salt unit and is owed a refund.

Germany's K+S paid about $1.58 billion for the Morton brand in April 2009, just as Dow was closing on its more than $16 billion buyout of Rohm & Haas.
The buyout of Morton, founded in 1848, made K+S the world's largest salt producer.

In a filing with a U.S. District Court, K+S said the sales agreement stipulated that the final price for Morton would be raised or lowered after the deal closed.

Based on several financial metrics, the final closing price should have been $1.56 billion and Rohm & Haas owes K+S $14.6 million, plus interest, K+S said in the lawsuit.

Rohm has not yet been served with the reported suit, but believes it is "unnecessary and without merit," a spokesman for Dow said in an emailed statement.
Dow Chemical sold the Morton assets the same day it bought Rohm.

K+S also claims that Rohm & Haas did not disclose certain Canadian pension obligations. The German company said it is seeking C$19 million due to the alleged nondisclosure.

The case is K+S AG v. Rohm & Haas Co, U.S. District Court, Southern District of New York, No. 10-cv-9689.