OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.

May 16, 2011

The Honorable Charles E. Grassley
United States Senate
Washington, D.C. 20510

Dear Senator Grassley:

Thank you for your August 12, 2010, letter to the Occupational Safety and Health Administration (OSHA) on behalf of your constituent, Mr. Alan J. Smith, regarding the use of sweep augers in grain storage bins. Mr. Smith asked for definitions of "guarded and non-guarded" sweep augers, referring to a December 24, 2009, OSHA letter of interpretation (copy enclosed). That letter of interpretation addressed an inquiry about a specific scenario involving a sweep auger, which OSHA's correspondent described as an "unguarded screw auger."

A sweep auger is a horizontal auger used to push grain remaining at the bottom of a storage bin toward the bin's discharge sump opening. It rotates around the discharge opening to "sweep" the grain toward that opening. Although the screw portion of the auger is often at least partially covered by some type of guard, the entire assembly consisting of the screw and the guard rotate around the bin. In addition, a guard cannot cover the entire screw assembly portion of a sweep auger, or the auger would not be able to function. Therefore, it is correct to describe a sweep auger as an "unguarded ... auger."

Mr. Smith's letter seeks guidance on when workers may be inside a grain storage bin while a sweep auger is operating. OSHA's grain handling standard, 29 CFR 1910.272, contains specific requirements that must be met before workers may enter most grain storage bins. This includes the requirement that "all mechanical, electrical, hydraulic, and pneumatic equipment which presents a danger" to the workers be "deenergized and ... disconnected, locked-out and tagged, blocked-off or prevented from operating by other equally effective means." 29 CFR 1910.272(g)(l)(ii) (emphasis supplied). Although Mr. Smith's letter refers to "non-automated" sweep augers, OSHA believes the vast majority of sweep augers, if not all of them, are powered by electrical or other energy covered by this standard.

There is no question that sweep augers present a danger to workers who are present while the augers are operating. Indeed, OSHA is aware of many fatalities, amputations, and other serious injuries resulting from workers entering grain storage structures to conduct maintenance or adjustments on sweep augers, even when those augers are equipped with guards. Most often, these occur when a worker's clothing, shoestring, or body parts become entangled in the rotating screw of the auger. The hazard is heightened because workers performing these operations are also susceptible to slip/trip hazards from uneven or moving grain.

Workers who enter grain storage structures to ensure that the machinery will resume moving forward have also been injured when they pushed the sweep with their feet or hands, or picked up a running auger. Other workers have been caught and injured by suddenly-starting, fast moving sweep augers operating in storage structures with near empty grain levels. In some cases, an auger may sweep the worker into the discharge sump, resulting in a grain entrapment. At least 26 workers were killed in grain entrapments last year, and the number of entrapments is increasing, according to researchers at Purdue University. There were more grain entrapments in 2010 than in any year since the researchers started collecting data on entrapments in 1978.

OSHA does not agree that its grain handling standard means that employers are unable to use sweep augers, as Mr. Smith suggests. If an employer can demonstrate that a worker in a storage structure is not exposed to hazards presented by the equipment, the standard does not require the equipment to be deenergized. For example, a worker would not be exposed to engulfment or entanglement hazards by standing on a guarded platform or catwalk that is sufficiently far away from areas where grain is being drawn from storage. See 61 Federal Register 9581, March 8, 1996 (copy enclosed).

In addition, there are alternatives to sending workers into a grain storage structure to conduct maintenance or adjustments to an energized sweep auger. For instance, an employer may choose to use a sweep auger with a higher horsepower, or use remotely operated tractors that can push a sweep auger through the grain.

Nor is a sweep auger the only means of removing grain from a mostly empty storage facility. Removal can also be accomplished through the use of a vacuum system, or workers can manually shovel and/or sweep remaining grain from a bin once the equipment is deenergized and locked out. Please keep in mind, however, that if the means of removing grain requires a worker to enter the grain storage structure, all hazards, including all engulfment hazards, must be controlled. See 29 CFR 1910.272(g)(6) and the enclosed OSHA Fact Sheet.

Additionally, if an employer has a different way of protecting workers, it may request a variance from a standard, or portion of the standard, authorized by section 6(b)(6)(A) of the OSH Act. Iowa operates its own occupational safety and health program under a plan approved and monitored by Federal OSHA and administered by the Iowa Division of Labor Services (DLS). Under this plan, Iowa's DLS promulgates and enforces, under authority of State law, occupational safety and health standards that are at least as effective as those of Federal OSHA, and is obligated to enforce its standards as effectively as Federal OSHA does. You may contact Iowa's DLS at the following address for more information about requesting a variance:

Iowa Division of Labor Services
1000 East Grand Avenue
Des Moines, Iowa 50319-0209
PH: (515) 242-5870
FAX: (515) 281-7995

The Iowa OSHA office would also be able to answer any questions about the specific citation Mr. Smith's employer received.

For small businesses, OSHA's On-site Consultation Program offers free and confidential advice on health and safety solutions with priority given to high-hazard worksites, including grain handling facilities. Through this program, small and medium-sized employers can obtain free advice on addressing hazards. On-site consultation services exist in every state, and they are independent from OSHA's enforcement efforts. On-site Consultation Program consultants, employed by state agencies or universities, work with employers to identify workplace hazards, provide advice on compliance with OSHA standards, and  assist in establishing safety and health management systems. More information is available at www.osha.gov or 1-800-321-6742.

We hope this response is helpful to you and your constituent. Thank you for your continued interest in occupational safety and health. If we can be of further assistance, please have your staff contact Sharon Block in the Office of Congressional and Intergovernmental Affairs at (202) 693-4600.


David Michaels, PhD, MPH