Oklahoma City-LSB Industries Inc. reported a huge increase in its Chemical sector operating income, which includes El Dorado Nitrogen Co., during the first quarter ending March 31, 2007. Chemical operating income was $7.7 million on sales of $73.7 million compared to the year-ago $1.8 million and $62.5 million, respectively. LSB also reported improved results for its Climate Control segment. LSB-wide, net income was $10.8 million ($.28 per diluted share) on sales of $147.4 million, versus the year-ago $3.0 million ($.14 per share) and $111.6 million, respectively.