LSB Industries to Build Ammonia Plant in El Dorado by Arkansas Business Staff Posted 8/15/2013 07:50 am Updated 2 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 stories older than 20 days. Purchase Now Already have archive access? Login to view this article.