For employees who store, transfer, deliver or apply anhydrous ammonia: where the rule applies, container location and markings, gas masks and emergency water, filling limits, attended transfers, hose protection, tank car unloading, and farm vehicle requirements.
Based on OSHA 29 CFR 1910.111 · about 3 min read
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The rule covers the design, construction, location, installation and operation of anhydrous ammonia systems, including refrigerated storage. It does not apply to ammonia manufacturing plants or to refrigeration plants where ammonia is used solely as a refrigerant.
Containers are marked, including the words Anhydrous Ammonia, design pressure, and the maximum fill level (unless filled by weight or using fixed level indicators).
When choosing a container location, the physiological effects of ammonia and nearby fire hazards are considered. Containers are outside buildings or in buildings or sections provided for that purpose.
Permanent storage containers are at least 50 feet from a dug well or other potable water source (except as part of a water-treatment installation).
Ammonia hose 1/2 inch OD and larger is marked at 5-foot intervals with Anhydrous Ammonia, maximum working pressure, manufacturer's name or trademark and year of manufacture, or the same information is on a nameplate permanently attached to the hose.
Stationary storage installations keep at least two suitable gas masks in readily accessible locations. Gas masks must be NIOSH-approved for anhydrous ammonia. NIOSH-approved full-face masks with ammonia canisters are suitable for emergency action involving most leaks, particularly outdoors; a self-contained breathing apparatus is required in concentrated ammonia atmospheres.
Stationary storage installations have an easily accessible shower or a 50-gallon drum of water.
Each bulk transport vehicle (except farm applicator vehicles) carries at least 5 gallons of water and a full face mask.
Non-refrigerated containers are not filled beyond the filling density limits in the rule. For the 87.5 percent by volume allowance on aboveground uninsulated containers, charging stops at the first sign of frost or ice on the outside and is not resumed until the frost or ice has disappeared (unless the temperature of the ammonia being charged is determined to be not lower than 30 degrees F).
An attendant must be continuously present in the vicinity during any ammonia transfer.
Containers are charged or used only with the owner's authorization, and gaged and charged only in the open atmosphere or in areas provided for that purpose.
Pumps and compressors are made or recommended for ammonia service.
Loading and unloading systems have devices (backflow check valves, excess flow valves or remote shutoffs) to prevent emptying a container if a hose is severed.
Tank car unloading is done by reliable persons properly instructed and given authority to monitor compliance with procedures. Caution signs (“STOP—Tank Car Connected” or “STOP—Men at Work”) are placed on the track or car and left up until the car is unloaded and disconnected. The siding is substantially level, and brakes are set and wheels blocked.
Tank motor vehicles carry at least two chock blocks, placed to prevent rolling whenever the vehicle is parked during loading and unloading.
Farm vehicle nurse tanks (1,200 gallons or less, used other than for applying ammonia to the soil; applicator containers larger than 250 gallons must meet these requirements too) carry at least 5 gallons of water, secure both hose ends in transit, and are marked “Caution—Ammonia” on each side and the rear end in letters at least 4 inches high (or marked per DOT regulations).
Fact-checked against the regulation text on October 09, 2026. This certificate records completion of awareness training based on OSHA 29 CFR 1910.111. It is not an OSHA card or license. 29 CFR 1910.111 has no general training requirement, so this certificate does not by itself qualify you for any task. Your employer must still insure that tank car unloading operations are performed by reliable persons properly instructed and given the authority to monitor careful compliance with all applicable procedures (29 CFR 1910.111(b)(13)(ii)), and must require the continuous presence of an attendant in the vicinity of the operation while ammonia is being transferred (29 CFR 1910.111(b)(12)(ii)).
This guide explains the rule in plain words. Always read the regulation itself and your employer's site-specific procedures.