OSHA Instruction CPL 2-1.4C November 8, 1996 Directorate of Compliance
Subject: Inspection of Grain Handling Facilities, 29 CFR 1910.272
A. Purpose. This instruction provides guidelines for inspections
conducted in grain handling facilities and clarifications of 29 CFR 1910.272.
B. Scope. This instruction applies OSHA-Wide.
C. Cancellation. OSHA Instruction CPL 2-1.4B, August 29, 1988, is
D. Action. Regional Administrators and Area Directors shall ensure
that all inspections of grain handling facilities are conducted in accordance
with the guidelines given in this instruction.
E Federal Agencies. This instruction describes a change that
affects Federal agencies. Executive Order 12196, Section 1-201, and 29 CFR
1960.16, maintains that Federal agencies must also follow the enforcement
policy and procedures contained in this instruction.
F. Federal Program Change. This instruction describes a Federal
Program change which affects State programs. Each Regional Administrator
1. Ensure that this change is promptly forwarded to each State
designee using a format consistent with the Plan Change Two-way Memorandum in
Appendix P, OSHA Instruction STP 2.22A, State Plans Policies and Procedures
2. Explain to each State designee as requested the technical
content of the change and the guidelines detailed in this
3. Ensure that State designees acknowledge receipt of this Federal
program change in writing to the Regional Administrator when the State's
intention is known, but not later than 70 calendar days after the issuance
(10 days for mailing and 60 days for response). This acknowledgment must
include a statement indicating whether the State will follow the guidelines
in this instruction or develop alternative guidelines.
4. Ensure that State designess submit a plan supplement in
accordance with OSHA Instruction STP 2.22A, CH-3, as appropriate, following
the established schedule that is agreed upon by the State and Regional
Administrator to submit non-Field Operations Manual/OSHA Technical Manual
Federal program changes.
a. The State plan supplement should be in the form of a State
directive or policy/procedure document, which details procedures for
implementing the safety guidelines in the State.
b. The State's acknowledgement of the Plan Change Two-Way
Memorandum may fulfill the plan supplement requirement if the appropriate
documentation is provided.
5. The RA shall review policies, instruction and guidelines issued
by the State to determine that this change has been communicated to State
G. Background. The standard for grain handling facilities, 29 CFR
1910.272, was promulgated on December 31, 1987, at Federal Register
Volume 52, No. 251 (52 FR 49592) and became effective March 30, 1988, except
for housekeeping provisions which were delayed by Federal Court Order until
August 1988. March 8, 1996, amendments were added in Federal Register Volume
61, No. 147 (47FR9578) and became effective April 8,1996.
1. The standard culminates several years of effort by OSHA in
response to the hazards found in grain handling facilities, particularly
fires and explosions. The final rule addresses both hazards to employees
presented by potential fires and explosions and other safety hazards (e.g.,
2. Although the final rule applies to all grain handling
facilities, it is not a "vertical" industry standard. That is, it is not
intended to address all hazards to be found in workplaces of this type.
Therefore, the standards contained in 29 CFR Part 1910 for general industry
and 29 CFR Part 1917 for marine terminals, as appropriate, will continue to
apply to grain handling facilities. 29 CFR 1910.272, however, takes
precedence inside the grain handling facility over other provisions in 29 CFR
1910 and 29 CFR 1917 for the specific hazards the grain standard
3. The amendments made in the March 8, 1996, Federal Register
revise paragraph (g) and create a new paragraph (h) addressing engulfment
hazards in bins, silos, and tanks and in flat storage structures,
H. Inspection Personnel.
1. Experienced Personnel Only. Only compliance safety and
health officers (CSHOs) who are well trained and experienced in grain
handling inspections shall normally be assigned to conduct inspections in
grain handling facilities. The Regional Administrator will ensure that an
appropriate number of such trained CSHOs are available for such
2. Expert Services. The Regional Administrator, in
consultation with the Regional Solicitor shall decide as soon as practicable
whether or not expert services from outside the Agency (such as expert
witnesses or an independent investigator) will be needed to support a grain
handling case properly. If so, such services shall be involved at the
earliest date practical.
I. CSHO Safety and Health. CSHOs shall take appropriate
precautionary measures for the particular hazards presented in grain handling
1. Personal Protective Equipment (PPE). In addition to
normal personal protective equipment, it is recommended that CSHOs conducting
inspections in grain handling facilities shall wear natural fiber (e.g.,
cotton), non-spark-producing clothing. It is recommended that CSHOs be
provided with appropriate flameretardant clothing.
2. Manlifts. Care shall be taken that Manlifts and other
means of access to upper levels of a facility are used by CSHOs only when
this can be done safely.
a. CSHOs shall conduct an in-depth safety evaluation of
manlifts, ladders, stairways, etc., in the facility before using them to gain
access to upper levels. If they are determined to be unsafe or not in
compliance, and no alternative safe means is provided, the CSHO shall stop
the inspection, follow normal enforcement procedures to achieve compliance,
and return to finish the remainder of the inspection after abatement of the
hazards has been verified.
b. Extreme caution shall be used on belt manlifts. Belt
manlifts, even when totally in compliance with OSHA standards (29 CFR
1910.68), pose a potential fall hazard to CSHOs. CSHOs shall utilize
alternate routes, when available, when they feel their safety is in question.
When using a belt manlift, CSHOs shall not carry clipboards or other
equipment except when it is secured in a bag or container that leave the
hands free (e.g., a secured bag with a neck strap).
c. CSHOs who are not familiar with the particular type of
manlifts used at the facility being inspected shall request specific hazard
training and/or instruction from an appropriately knowledgeable employer
J. Standard Clarifications. The following clarifications of
specific provisions of 29 CFR 1910.272 are provided to assist CSHOs in
conducting inspections at grain handling facilities.
1. Scope and Application of 29 CFR 1910.272(a) and (b).
a. The majority of facilities covered by the standard are in
Standard Industrial Classifications (SICs):
(1) 2041, Flour and other Grain Mill products;
(2) 2044, Rice Milling;
(3) 2048, Prepared Feeds and Feed Ingredients for Animals
and Fowls, Not Elsewhere Classified;
(4) 4221, Farm Product Warehousing and Storage; and
(5) 5153, Grain.
b. Facilities in the following SICs are generally not
covered by the standard:
(1) 2043, Cereal Breakfast Foods;
(2) 2045, Blended and Prepared Flour;
(3) 2047, Dog, Cat, and Other Pet Food; and
(4) 2051, Bread and Other Bakery Products, Except Cookies
c. Covered workplaces may also be found in other SICs (such as
those listed at I.I.b. above) where they are not the primary business. If a
facility has a grain elevator onsite, which receives, handles, stores
and ships (including transfer to another part of the facility) a bulk, raw,
agricultural commodity, the standard applies to the grain elevator. An
example of this type of facility is a grain elevator used in support of a
brewery. (The important factor is that a bulk, raw, agricultural commodity
enters the facility, is handled and stored, and then leaves the facility in
the same form: a bulk, raw, agricultural commodity.)
d. The standard does not apply to "seed plants" which handle
and prepare seeds for planting of future crops; however, such facilities are
covered by the Part 1910 Standards, including 1910.146 and 1910.147.
Agricultural operations are not covered in Part 1910; therefore, 1910.272
does not apply to on-farm storage or feed lots.
e. If the CSHO is uncertain as to what constitutes "raw
agricultural commodities," or the explosibility index of agricultural dusts,
references include the Bureau of Mines report and the National Academy of
Sciences' "Classification of Combustible Dust in Accordance with NEC." (See
Appendix A, References, of this instruction.)
2. Emergency Action Plan, 29 CFR 1910.272(d).
a. 29 CFR 1910.38(a), Employee emergency action plan, requires
the emergency action plan to be in writing except for employers with 10 or
fewer employees. However, employers with 10 or fewer employees will still
have to comply with 1910.38(a) requirements and be able to substantiate that
the plan is being communicated orally in an effective manner.
b. All employees, including truck drivers, sales and office
personnel, seasonal employees, and part-time employees, shall be included in
determining the total number of employees at a given
3. Training, 29 CFR 1910.272(e). Employees are required
to be trained in the recognition and prevention of hazards associated with
grain handling facilities, especially those hazards associated with their own
a. CSHO's shall verify whether employees are trained in all
aspects of safety and health related to their job tasks. They shall also
verify whether employees are trained not to introduce ignition sources
(sparks, arcs) through the use of electric tools, and through grinding or
drilling in hazardous areas containing combustible dusts. Other ignition
sources include welding, cutting, use of open flames or smoking materials
into hazardous areas.
b. The standard does not require that training records be kept
to verify that employees have been adequately trained. Therefore, the CSHO
shall substantiate the adequacy of training by reviewing the employer's
training records, if offered by the employer, and by interviewing a sample of
c. Employers shall commence the training of employees prior to
d. In addition to the training information and references
listed in Appendix A.3. and Appendix C of the standard, see also Appendix A.
References, of this instruction.
4. Hot Work Permit, 29 CFR 1910.272(f).
a. If a permit is issued, the employers' representative need
not be at the specific "hot work" site during the entire time the work is
performed. It is reasonable to expect that the employer should monitor
frequently--at least each shift--to ensure those permit requirements are
b. If the employer elects to have a representative present in
lieu of a written permit, the employer must still follow the same
requirements as if a permit were issued in accordance with 29 CFR
1910.252(a). The representative must in this situation be present for the
entire duration of the job.
c. The term "flame producing" used in the definition of "hot
work" at 29 CFR 1910.272(c)(4) includes ignition sources (sparks, arcs)
produced by operations such as welding, cutting, and brazing. Hot work
permits are necessary for these types of operations.
5. Entry into Grain Storage Structures 29, CFR 1910.272(g).
This paragraph amends the former paragraph (g) in several ways.
However, bins, silos, and tanks continue to be covered by new paragraph (g).
Flat storage structures including certain tanks, which do not have any
atmospheric hazards, are now covered in a new paragraph (h).
a. A life line (body harness attached) used for entry
procedures shall be of such length that it would not allow the employees to
sink any further than waist deep in the grain.
b. If the employer or representative (who would otherwise be
authorized to issue the entry permit) elects to remain present during the
entire operation, a written permit is not required. All other provisions of
1910.272(g) must still be complied with.
c. When the CSHO can verify that fumigants have been applied,
the employer's program for fumigation procedures and testing of the
atmospheres for toxicity shall be reviewed. The hazard analysis under 29 CFR
1910.132(d) should be reviewed for appropriate PPE being used.
d. The CSHO shall ask the employer to verify the procedure(s)
used to ensure that testing equipment used to determine hazardous
atmospheres, including but not limited to pesticides, fumigants, dust, and
oxygen deficiency is properly calibrated and maintained prior to
e. If testing the atmosphere indicates oxygen deficiency
and/or the presence of toxic and flammable gases above the specified limits,
the CSHO shall ensure that employers are provided with the required
ventilation and/or PPE before entry.
f. Aeration fans can constitute forced air ventilation even
when grain is covering the aeration ducts, provided that the air exits the
duct at above the grain level.
g. The CSHO shall evaluate the type of rescue equipment
available to determine its adequacy for each particular situation, i.e.,
types and configurations of bins, which may be somewhat different at each
facility. The employer may have to establish that the equipment is suitable
to perform the task for the particular facility.
h. Employees are forbidden to walk or work on the surface of
the grain which is to support them until the employer has verified that
engulfment hazards do not exist as a result of a bridging condition, air
pocket or void space below the surface of the grain, or that the depth of
grain is not sufficient to present engulfment hazard in the specific bin,
silo or tank. Probe tests sufficient to detect any air pockets or void
spaces may be one way to assess the stability of the grain surface. However,
if a worker must stay on the grain to conduct such tests, the worker must be
protected from engulfment during the tests. Grain depth may be analyzed
based on use and documentation to show that there are no recent draw-off
problems, moisture problems from open hatches, leaking roofs, etc., and that
any previous problems have been corrected. Certain agricultural commodities
such as flax, millet, and oil seeds present additional hazards that must
be addressed by the employee if they are involved in the entry. The
employer must be able to show the lockout and tagout procedures are in effect
to prevent any grain or grain product conveying machinery from operating
while the employee is supported on the grain. The employer is to verify that
all employees, before being permitted to walk on stationary grain, will have
completed the training requred in paragraph 29 CFR
i. Employees are forbidden to "walk down grain" for the
purpose of making grain flow to the draw-off equipment which may or may not
j. When employees are to free caked, plugged, or bridged grain
to move it, such as to a center draw off, the employee's body weight is to be
supported in a boatswain's chair with a life line suspended from the top.
The boatswain's chair shall be supported by slings attached to a suspended
rope, and shall be designed to accommodate one person in a sitting position.
The CSHO shall ensure that employers provide a body guard equipped with
communication mode, who maintains contact with the employee entering the
sile, bin or tank. The CSHO shall ensure that the observer or the body guard
is trained and equipped for rescue operations. The employee is expected to
use a tool, such as a long rod, to force grain toward the draw off equipment
or to remove it from the sides of the grain storage structure. The employer
is to verify that the employee will not be exposed to mechanical hazards.
Where the employer states a greater hazard exists, both engulfment and
mechanical hazards must be addressed by alternate means.
k. Employees are permitted to walk on the grain when cleaning
bottoms of bins, or for other purposes, without a lifeline and harness when
the employer has verified that the depth of the grain will not result in an
engulfment hazard. The employer is also to verify that the employee will not
be exposed to mechanical hazards. Employers shall not permit employees to
enter silos whenever bridging conditions or grain funnelling (side building)
6. Entry into Flat Storage Structures 29 CFR 1910.272(h).
This new paragraph addresses grain storage structures that will
not empty completely, without mechanical equipment or manual means being
used, and can be entered from the ground level through regular or larger
doorways or openings. Entry into these grain storage structures under this
section is permitted only in the absence of actual or potential atmospheric
hazards. Entry into those that may have atmospheric hazards is covered
in the new paragraph (g). Flat storage structures may include flat bottom
tanks, buildings where grain is stored on the floor, tents, or other
structures where grain is stored in a pile in bulk on a flat bottom
a. When employees are permitted to walk on the grain product
without a restraint system, such as may be done by Federal or State grain
warehouse inspectors, the employer must show that all equipment such as, but
not limited to augers, transport equipment shall be deenergized, disconnected
and locked out. The employer shall demonstrate that lockout and tagout
procedures are in effect to prevent any movement of a grain or grain product
in the area where the employee is expected to walk. Also the employer must
verify that there is no recent history of draw-off problems that could create
cavities in the grain pile. The employer is to verify that those employees
involved in this task will have completed the training required in paragraph
29 CFR 1910.272(e) before walking on the grain or grain
b. Where lifelines are used, their length will not allow the
employees to sink any further than waist deep in the grain.
c. "Walking down grain" for the purpose of making the grain
flow or any other purpose is prohibited in flat storage structures. See item
d. No employee shall be permitted to work underneath bridging
conditions or in any location where the possibility of engulfment from
falling grain exists.
7. Contractors, 29 CFR 1910.272(i).
a. The intent of the phrase "shall inform": is that an
employer is to provide specific instruction to contractors on the safety
rules of the facility, including applicable provisions of the emergency
action plan. Simply providing a copy of the safety program, for example,
would not ensure that the contractor has received sufficient information to
take adequate precautions to prevent exposure to potential
b. A "contractor" is an individual, group of individuals,
firm, or entity who enters the premises for the purpose of performing work
and who may be exposed to hazards during the course of performing work. This
normally would not include service or inspection-related persons, e.g.,
vendors, delivery personnel, or insurance representatives, unless they pose
or could create a hazard to facility employees while performing their
8. Housekeeping--General, 29 CFR 1910.272(j). The standard
incorporates strict and clear requirements for employers to adopt
housekeeping practices determined best to reduce accumulations of grain
a. 1910.272(j)(1) is applicable to grain elevators and those
mills specified at 29 CFR 1910.272(b)(l), application.
b. 1910.272(j)(2) applies only to grain elevators and not to
processing or mill operations.
c. In order to substantiate violations of the employer's
housekeeping programs, CSHOs shall carefully prepare the evidence by
documenting the specific procedures the employer utilizes to keep dust
accumulations at a minimum. Such documentation must address at least the
(1) Manual dust removal procedures, including frequency and
(2) Condition and effectiveness of the system, including
maintenance and repair on closed conveyance systems. (i.e., leaking spouts,
worn-out gaskets, flanges, and other similar emission
(3) Representative measurements and photos shall be taken
to document apparent violations of the general housekeeping provision of the
standard. (See 29 CFR 1910.272, Appendix A.) It maybe necessary to take
several measurements at specific locations within the general area. The
locations shall be identified on a plant sketch.
NOTE: Because of spark-producing potential, no
equipment including flash bulbs and electronic flashes (cameras) or
electrical equipment, shall be used in hazardous areas in grain handling
facilities unless the equipment is approved for use in these types of
(5) Areas of particular concern beyond the priority areas
are the grain transfer points, such as galleries (bin floors) and
(6) Representative samples of dust shall be taken in areas
where apparent violations of the general housekeeping provision exist to
verify organic dust percentage, moisture content, and particle size. Sample
quantities will not normally have to exceed one-half pint at each
(7) When the employer elects to utiliie additives to
control the dust rather than collection and other control methods, the CSHO
shall document the types used, specific application points and application
rate, and shall verify the effectiveness of the method through appropriate
sampling and measurement.
9. Housekeeping--Priority Areas in Grain Elevators, 29 CFR
1910.272(j)(2). The standard establishes a l/8-inch action level for
housekeeping regarding grain dust accumulations in priority areas in grain
elevators. This provision requires either an initiation of a cleanup
wherever the 1/8 inch action level is exceeded, or an alternative method
which provides "equivalent safety." If the employer chooses not to initiate
cleanup actions whenever the grain dust level exceeds 1/8 inch, and instead
chooses an alternative method, such as treating a grain stream with oil
additives which inhibit the combustibility of any dust that is emitted from
the grain handling system or "wetting down" the areas of dust accumulation
using either an oil-or water-based solution, as a means of compliance of this
standard, then the employer must demonstrate that those accumulations (oil or
water treated) do not pose a greater fire explosion hazard than would exist
if the grain dust was removed prior to its accumulation of more than 1/8
a. A representative number of measurements, photos, and
samples shall be taken of all floor areas within a priority area to document
a violation of the 1/8 - inch action level; they shall be noted on a plant
NOTE: Because of spark-producing potential, flash bulbs
and electronic flashes shall under no circumstances be used in grain handling
b. The CSHO shall use professional judgment to assess the
extent of a hazard presented by a given identified accumulation of grain
dust. Small amounts of dust accumulation in isolated spots of the floor
would not normally be classified as a violation of the requirement.
Additionally, all other types of surfaces within the priority areas that have
excessive accumulations of dust shall be identified and documented as a
potential violation of the overall housekeeping program specified by
c. A priority area shall not be considered to include sections
that are separated by walls, partitions, and/or control rooms or offices with
positive pressure and self-closing doors.
10. Blowdown Operations, 29 CFR 1910.272(j)(3).
a. Equipment may be operated during blowdown operations if the
following conditions exist:
1. The equipment is dust-tight and dust ignition-proof; or
the equipment is intrinsically safe (i.e., insufficient heat or thermal
energy to ignite combustible dust); and
2. The bearings are effectively monitored; and
3. An effective preventive maintenance program has been
b. Isolation techniques, shrouding etc., should be encouraged
and can be acceptable to minimize dust suspension and dispersal of
11. Grain and Product Spills, 29 CFR 1910.272(j)(4).
Product spills, especially in flour mill operations, should receive prompt
attention. These spills shall be cleaned up after identification. Grain
spills do not present the same hazard as product spills and should be cleaned
up as soon as practical after identification.
12. Grate Openings, 29 CFR 1910.272(k). Employers should be
encouraged to utilize magnets and openings as small as possible in the
receiving grate to minimize the hazard potential.
a. In special circumstances where commodities (such as corn
cobs) cannot pass through the specified-sized grate openings (maximum width
of 2.5 inches or 6.35 cm.), grates with larger openings may be used to
accommodate the commodity if magnets are used at the receiving pit or if
suspended magnets are used over conveyance systems prior to entering the boot
of the elevator leg.
b. Where applicable, CSHOs shall evaluate the compliance of
grate openings with 29 CFR 1910.23.
13. Filter Collectors, 29 CFR 1910.272(1). Product and/or
process filters are not covered by this paragraph. An excellent reference
for both the CSHO and the employer to evaluate and aid in abatement of
problems with filter collectors is the National Academy of Science
publication "Pneumatic Dust Control in Grain Elevators." (See Appendix A,
References, of this instruction.)
14. Preventive Maintenance, 29 CFR 1910.272(m).
a. The standard does not require a specific frequency for
preventive maintenance. The employer is permitted flexibility in determining
the appropriate interval for maintenance provided that the effectiveness of
the program can be demonstrated.
b. The CSHO shall particularly document and analyze the
program and its effectiveness based on the time period. The program must be
adequate for the peak period, such as during the harvest season. Particular
attention should therefore be focused on the harvest season. If the
inspection is being conducted at a time other than harvest season, the CSHO
shall conduct evaluation of programs (e.g., by interviewing sufficient key
employees) to determine conditions and adequacy of preventive
c. Manufacturers' recommendations for equipment can assist
CSHOs in determining the adequacy of maintenance frequency
d. Bearings not associated with inside bucket elevators (i.e.,
those located on gallery and tunnel belts, mechanical equipment) must have
inspections and proper lubrication as required by
15. Emergency Escape, 29 CFR 1910.272(o)(1).
a. Employers will need to provide at least one emergency
escape from the headhouse or any floor between the headhouse and ground
level, in accordance with 29 CFR 1910, Subpart E. Controlled descent devices
and escape ladders are acceptable means of escape from galleries and
bindecks. Manlifts (belt, caged, manual) are not considered an adequate
means of escape; however, a fixed ladder in a manlift shaft is acceptable.
Scale floors and headhouses must still meet appropriate provisions in 29 CFR
1910, Subpart E.
b. If controlled descent devices are used, they shall be
adequate to accommodate employees or occupants from a given area of the
facility. All employees who work in the area served by the controlled
descent devices shall be trained in their use and provided with a sufficient
amount of interface equipment such as body harness(es) and line to safely
reach the ground or other walking surface.
16. Continuous-flow Bulk Raw Grain Dryers, 29 CFR
1910.272(p)(l)(ii). The CSHO can rely on the manufacturer's
recommendations for maximum operating temperature of the drying section to
determine or evaluate what is considered "excessive" temperature.
17. Inside Bucket Elevators, 29 CFR 1910.272(q). Elevator
legs in mills will still have to comply with the requirements in
1910.272(m)(1) for preventive maintenance even though they are not covered by
1910.272(q). (See 29 CFR 1910.272(b), Application.)
18. 29 CFR 1910,272(q)(2). When an employer has
documentation that will identify that the belt characteristics meet the 300
megohm requirement for belts purchased after March 30, 1988, it will be
considered to be in compliance.
19. 29 CFR 1910.272(q)(4)(ii). If any portion of the
bearing (including inner dust seal) is making contact with the interior of
the leg casing, the bearing will be considered partially inside the
20. 29 CFR 1910.272(q)(6). The preamble of the standard
indicates that the hydraulic boot takeups can be used in lieu of a belt
alignment monitor. This is primarily designed to ensure proper belt tension;
however, if there are features of the device that ensure proper alignment, it
will be accepted.
21. 29 CFR 1910.272(q)(7).
a. Permanent Storage Capacity. In determining the
permanent storage capacity of an employer's workplace, the CSHO should
consider the total storage for the entire complex. This storage would not
necessarily have to be serviced by the same house or leg. It can comprise
separate facilities that are a part of the same complex, e.g., an old wooden
house with a new concrete facility across the road where employees of the
same manager work at both locations. Those facilities or complexes where
there are separate houses beyond a given geographical area (e.g., further
apart than a square block) would not be considered in the total quantity.
Temporary storage such as grain piled outside would also not be
b. Daily Visual Inspection. The employer will verify
the methodology being used to ascertain proper observation. The employer
should also have this as a part of training and the preventive maintenance
program and it should be properly documented.
22. 29 CFR 1910.272(q)(8)(ii). The employer will certify
that concentrations are in fact, at least 25 percent below the lower
explosive limit (LEL). The employer may use instruments, tests, surveys, or
data developed on legs that are identical in size, configuration, speed,
etc., to meet the intent of the requirement.
K. Additional Documentation to Support Violations--Construction
and Functional Details. The CSHO shall obtain the following
information to support violations.
1. Type and age of facility.
2. Type of construction including;
a. A sketch of the workhouse showing names of floors from the
b. Type of fire protection/fire alarm system;
c. Evacuation plan, with the location of emergency exits
including fixed ladders;
d. Explosion venting capability;
e. Type of fumigation systems; and any other significant
3. Type of grain receiving, handling and shipping procedures and
equipment; number and location of elevator legs with a description of belt
type and size, bucket design, belt speed, etc.; grain drying facilities,
location, type of fuel, safety devices, etc.
L. Minimum Documentation Necessary for Electrical Hazards.
Electrical installation and equipment in grain handling facilities are
covered under 29 CFR 1910.301 through 1910.399. Most areas of grain handling
facilities where dust accumulations can occur are considered to be hazardous
locations, as defined in 1910.307.
1. Hazardous Locations, 29 CFR 1910.307 is a performance-oriented
standard which permits the employer to follow any of three options:
equipment, wiring methods, and installations of equipment in hazardous
(classified) locations must be either intrinsically safe, or approved for the
hazardous (classified) location, or safe for the hazardous (classified)
a. If the employer chooses the third option of providing
equipment that is "safe for the hazardous location," then the employer must
demonstrate that the equipment is of a type and design that will provide
protection from Class II hazards (see classifications of hazardous locations
in 1910.399(a)); i.e., that it is at least as safe as equipment following the
guidelines contained in the National Electrical Code. (NEC).
b. Acceptable evidence might be test date, manufacturer's
information, approved equipment markings, or proof of conformity with the
requirements of the edition of the NEC in effect at the time that the
equipment was installed together with proof that the equipment has not been
2. Classification of an area as Class II, Division 1 (see
1910.399(a)), will require documentation of the possibility that minimum
explosive concentration of dust might occur under normal operating
conditions. Such concentrations normally could occur within the bucket
elevator enclosure, within scales, in the upper garner, or at open grain
transfer points that create airborne dust clouds. They may occur at
unvenilated loading points or discharge points of equipment.
3. Classification of any area with a grain handling facility will
normally, at the very least, be Class II, Division 2, as defined at 29 CFR
4. Some locations within a facility such as rooms or offices that
are provided with positive pressure ventilation and self-closing doors, and
are so constructed that the room will not allow grain dust to enter during
normal operating conditions, are considered as nonhazardous
5. Any electrical citation issued must be adequately documented in
the case file. If the citation involves a hazardous location, such
documentation must address the following matters to the degree
a. Type and quantity of accumulated grain dust, the amount
likely to be in suspension, the conditions likely to give rise to such
suspensions and their extent; the length of time over which such dust
deposits have been accumulating together with any evidence of charring of
layered dust; the ignition temperature of the dust and the humidity
conditions within the facility at the time of the inspection, if known (local
atmospheric data my be obtained from the National Weather Service); evidence
supporting the possibility that dust deposits or suspensions could be
ignited. (See also M of this instruction regarding laboratory
b. Location and type of potential electrical ignition sources;
type and condition of electrical equipment located in the area; evidence that
electrical equipment is not safe for the location.
c. The presence or likelihood of mechanical failure or
electrical malfunctions or abnormal operation of machinery or equipment;
combinations of factors which could result in explosive
d. Degree of confinement at the location.
M. Laboratory Support--Dust Sample Collection.
1. The Salt Lake City Analytical Laboratory has the capability to
analyze bulk grain dust samples for:
a. Particle size.
b. Combustible fraction of sample and percent combustible
c. Minimum explosive concentration.
2. Dust sample collection and preparation for laboratory analysis
shall be performed in the following manner:
a. Collection size of sample will be:
(1) Approximately one-half pint (0.25 liter) concentration
of dust to determine particle size, combustibility and moisture
(2) Approximately one quart (1.0 liter) for analysis for
minimum explosive concentration
b. Place the sample in a wide-mouth plastic container with a
tight-fitting screw cap. Do not use plastic bags.
c. Seal the containers with an OSHA Sample Seal. Package the
containers securely, using packing materials to cushion them during
d. Follow normal OSHA chain-of-custody procedures for all
aspects of sample handling.
e. Indicate on Form OSHA 91A, Item 30, that grain dust tests
(the analysis described at L.1. above) are being requested.
Joseph A. Dear Assistant Secretary
DISTRIBUTION: National, Regional, and Area Offices All Compliance Offices
State Designees NIOSH Regional Program Directors 7(C)(1) Project Managers
APPENDIX A References
The primary list of references relating to grain handling facilities is
contained in Appendix C of 29 CFR 1910.272. The following sources, some of
which have been mentioned in this instruction, may prove useful in assessing
compliance with the standard.
1. Bureau of Mines Report of Investigation--5753. See preamble to
the standard, 52 FR 49601, for description.
2. Classification of Combustible Dust in Accordance with NEC.
National Academy of Sciences, Washington, D.C. Available from National
Technical Information Service, Springfield, Virginia 22151.
3. Prevention of Grain Elevator and Mill Explosions. National
Academy of Sciences, Washington, D.C. Available from National Technical
Information Service, Springfield, Virginia 22151.
4. Pneumatic Dust Control in Grain Elevators. National Academy of
Sciences, Washington, D.C. Available from National Technical Information
Service, Springfield, Virginia 22151.
5. The Country Elevator Safety and Health Guidebook. Part of the
"Grain Industry Safety and Health Center--Training Series," published under
USDOL Grant No. E9F5B271. Grain Elevator and Processing Society, P.O. 15026,
Commerce Station, Minneapolis, Minnesota 55415-0026.