LSB Industries to Build Ammonia Plant in El Dorado by Arkansas Business Staff Posted 8/15/2013 07:50 am Updated 5 years ago LSB Industries Inc. of Oklahoma City says it will build a 375,000 ton per year ammonia plant in El Dorado. Want the Full Article? Get Unlimited Archive Access for $19.95 per Year Readers must pay to access articles older than 15 days. Articles newer than 15 days are not included in this offer. Purchase Now Already have archive access? Login to view this article.