Safe Fertilizer

Honeywell and fertilizer maker J.R. Simplot have agreed to build the first commercial facility for Sulf-N 26, a granular fertilizer that is comparable to ammonium nitrate but would be ineffective as a bomb material. Ammonium nitrate combined with fuel oil was used in the bomb that destroyed the Alfred P. Murrah Federal Building in Oklahoma City in 1995.

Sulf-N 26 is made with a patented Honeywell process that chemically fuses ammonium sulfate, which acts as a fire retardant, and ammonium nitrate. The product is a stable molecule that delivers nitrogen to crops.

The Department of Homeland Security has proposed a rule that would regulate the manufacture and sale of fertilizer containing more than 30% ammonium nitrate because of its misuse as an explosive. Honeywell says it does not expect Sulf-N 26 to be regulated if the proposed DHS rule goes into effect.

In contrast to ammonium nitrate, which is 34% by weight nitrogen, Sulf-N 26 is 26 wt% nitrogen and 14 wt% sulfur. Ammonium sulfate, with 24 wt% sulfur, is not appropriate for use on many types of soils.

According to the agreement, Honeywell will engineer, construct, and own a modular facility to produce the fertilizer at Simplot’s Lathrop, Calif., site. Honeywell generates ammonium sulfate as a by-product of making caprolactam, a nylon feedstock, in Hopewell, Va. Simplot will operate the new facility and sell the fertilizer in western North America. The firms plan to begin producing Sulf-N 26 by early 2013.