General Laboratory Safety Checklist
A. General Laboratory Safety Information
1. Do lab personnel know the location of safety plans? (Chemical Hygiene Plan,
Radiation Safety Manual & Carcinogen/Highly Toxic Chemical Work Procedures)
Every laboratory using hazardous chemicals, compressed gases, cryogens or other
chemical, physical, biological or radioactive hazards must have access to safety
plans and safety reference materials available through the Office of
Environmental Health & Safety Web page (http://www.depts.ttu.edu/ehs/). Every
laboratory employee should be able to readily access safety plans and reference
materials. Thoroughly review all applicable safety plans with laboratory staff.
Provide them as a handy reference for developing safe laboratory operations.
[OSHA 29CFR1910.1450 (e) (2)]
2. Do lab personnel know the location of MSDS’s and how to access them?
Distributors must provide a Material Safety Data Sheet (MSDS) for each hazardous
chemical or compound that they sell. The MSDS summarizes important hazard
information and must be readily available during all working hours to be used as
a reference for lab personnel. In the event of an accident or incident,
emergency responders will first consult the MSDS’s so that safe and successful
remedial actions may be planned and initiated. Laboratory supervisors are
required to maintain any MSDS’s that are received with incoming shipments of
hazardous chemicals, and ensure that they are readily accessible to laboratory
employees. All lab staff must be capable of retrieving an MSDS for any chemical
in the lab. MSDS’s can be accessed on the web at the following address.
[OSHA 29CFR 1910.1450 (f) (iii) (v), (h) (1) (ii); OSHA 29CFR 1910.1200 (b) (3)
(ii)] (Notebooks of MSDS’s in laboratory and access available through the
EH&S Web Page)
3. Are chemical names on primary and secondary containers?
Manufacturers are required to label every chemical container with hazard
information that includes chemical name, physical and health hazard information,
and name of manufacturer. These labels relay valuable information that can
assist in hazard evaluation and control, and cannot be removed or defaced from
the original container unless the contents have been altered or removed.
Secondary containers that will remain in use for a period of time (storage
vials, squirt bottles) should bear an abbreviated label that includes chemical
name and hazard warning words such as flammable, caustic, sensitizer,
carcinogen, absorbed through the skin, etc. [OSHA 29CFR 1910.1450 (h) (i)]
4. Is radiation signage in place where needed?
Radioactivity work areas, laboratories and containers of radioactive materials
must be posted with appropriate warning signs.
5. Is biohazard signage in place where needed?
Areas where human blood or other potentially infectious materials are stored or
used must bear the universal biohazard symbol. Researchers working with or
storing biosafety level 2 or higher organisms should also utilize the universal
biohazard warning. Appropriate locations for biohazard signs include laboratory
entrance, incubator, refrigerator, and waste containers. [OSHA 29CFR 1910.1030
(g) (1) (i); Biosafety in Microbiological and Biomedical Laboratories p. 14, 20]
B. Personal Protective Equipment
1. Are chemical resistant gloves available and worn during procedures?
To choose the best glove for a particular operation one must weigh the ability
of the glove material to resist permeation and degradation by the chemicals in
use against the dexterity needed to conduct the experimental protocol. There is
no single glove material universally resistant to all classes of chemicals;
glove selection must be individualized for each experimental protocol.
Sometimes, a combination of glove types is needed in order to provide adequate
protection against particularly toxic substances. Wearing the wrong type of
glove can be more hazardous than wearing no gloves at all since, if a chemical
migrates through the glove, it will be held in prolonged contact with skin.
Disposable latex and nitrile gloves, frequently used in lab settings because of
the high degree of tactile sensitivity and dexterity that they offer, are
chemically resistant to a limited number of chemicals. It is essential, then,
that laboratory staff diligently select and consistently use appropriate
chemical protective gloves. This is particularly important when using toxins
that can be absorbed through the skin. [OSHA 29CFR 1910.132 (a); OSHA 29CFR
1910.1450 (f) (4) (c); Prudent Practices in the Laboratory p. 83, 132-133]
2. Is eye protection available and worn during procedures?
The eyes are particularly sensitive to chemical or physical insult and should be
protected at all times against chemical splashes or sprays, flying particles, UV
radiation and other hazards. Chemical manipulations, handling glassware, systems
or components under pressure or vacuum, lasers, and UV light all present eye
hazards to the user. Appropriately selected eye protection is needed for these
and other procedures. ANSI approved safety glasses with side shields provide
impact protection and are the minimum level of eye protection appropriate for
laboratory work. Ordinary prescription eye glasses do not provide impact
protection or splash protection and, used alone, are not adequate eye protection
in the laboratory environment. Protection against chemical splashes and sprays
is only achieved by the use of chemical splash goggles or a face shield / goggle
combination. Where lasers having exposed beams are in use, laser goggles with
wavelength matched lenses are required. UV protection for the face and eyes can
be achieved by wearing a face shield fitted with polycarbonate lens. [OSHA
29CFR 1910.132 (a); Prudent Practices in the Laboratory p. 132]
3. Is protective clothing available and worn during procedures? (lab coat,
Lab coats not only protect street clothing from being soiled, they also provide
an additional layer of splash and burn protection and help protect family
members by reducing take-home-toxics. Protective apparel should always be worn
if there is a possibility that personal clothing could become contaminated with
chemically hazardous material. Laboratory coats should be worn buttoned, with
the sleeves rolled down. Additional protective clothing may be required
for certain high risk activities, use of large volumes, or where drenching may
occur. [OSHA 29CFR 1910.132 (a); Prudent Practices in the Laboratory p. 131]
4. Are respirators available or in use only with prior EH&S approval?
The primary objective in controlling occupational exposures is to prevent
contamination of the work atmosphere. This shall be achieved first by use of a
chemical fume hood, or other enclosure. It is only if engineering controls are
ineffective at maintaining exposure below the permissible limits that
respiratory protection can be considered. Respirators are sometimes referred to
as masks. To ensure that proper procedures are followed and that regulatory
burdens met, EH&S must pre-approve all respirator selection and use. Please call
Richard Whitehead at 742-3876 in the Office of Environmental Health & Safety if
laboratory personnel use masks or respirators when weighing or using hazardous
chemicals. [OSHA 29CFR 1910.134 (a) (1); OSHA 29CFR 1910.1450 (i)]
1. Are aisles free of slip, trip and fall hazards?
Among the most common injuries in laboratories are back injuries from slipping,
tripping, and falling. Even though space may be at a premium, pieces of
equipment, cartons, bottles and other supplies placed haphazardly in the aisles
or precariously on shelves pose a hazard to all who enter the lab. Glass bottles
placed on the floor near work spaces often end up tripping personnel, resulting
in a large chemical spill. Extension cords, hoses and other items stretched
across walkways can be easily overlooked, causing persons navigating the hallway
to stumble and fall. The danger presented by slipping, tripping and falling
hazards is compounded when visibility is limited and quick escape is essential,
as in a lab fire or other emergency action. [OSHA 29CFR 1910.22 (a) (1); Prudent
Practices in the Laboratory p. 60, 120]
2. Are bench tops free of excess storage and materials not in use?
There is a definite correlation between orderliness and level of safety in the
laboratory. Ample space in which to work that is free of clutter results
in far fewer inadvertent chemical spills, accidental mixing of incompatibles, as
well as splashes or other exposures. Clean up the work area upon completion of
an operation or at the end of each work day. Replace those items that are not
needed for immediate use to their proper locations. [OSHA 29CFR 1910.22 (a) (1);
NFPA 45 7-2.3.1; Prudent Practices in the Laboratory p. 72-73]
3. Bench tops and bench liners free of visible contamination?
Even the most inconsequential spill should be cleaned up at the time of release.
Materials present on surfaces can add to personal exposures through inhalation
or skin absorption. Some chemicals, if not cleaned up properly, will react
with liner paper or other organics resulting in a fire. Bench liners, if used,
should be changed regularly and immediately after a spill or other signs of
contamination. [OSHA 29CFR 1910.141 (a) (3)]
4. Is broken glass segregated from regular trash?
Broken glass should be collected separately from regular trash. This container
should be puncture resistant and clearly marked “Broken Glass.” By segregating
these items we prevent custodial staff and other personnel from receiving cuts
due to the presence of hidden objects in the regular waste stream. It is
important to keep in mind that objects considered “sharps” under the Bloodborne
Pathogens Standard (needles, scalpels) must be collected and disposed
separately; properly labeled sharps disposal containers must be used for this
purpose. The glassware that is contaminated with hazardous materials (chemical,
biological, or radioactive) should not be placed in the regular trash.
Contaminated glass should be collected for disposal by EH&S. [Prudent Practices
in the Laboratory p. 39, 148]
5. Are handwashing facilities available? (soap, paper towels)
Lab personnel should wash their hands often to remove trace amounts of chemical
contamination. Hands should always be washed before leaving the lab and before
eating, drinking, applying cosmetics or smoking. In order to follow proper lab
hygiene, a sink equipped with soap and water, as well as paper towels is needed.
Supervisors should ensure that handwashing supplies are available and well
stocked. [OSHA 29CFR 1910.1030 (d) (2) (iii); OSHA 29CFR 1910.1450 (f) (4) (c)]
D. Fume Hoods
1. Are fume hood tagged with an inspection sticker dated within past year?
Fume hoods must be inspected every year, and tagged with information concerning
the linear flow rate and the date the inspection was conducted. Environmental
Health and Safety (EH&S) is responsible for performing this service to the
2. Are chemical fume hood used for volatile, flammable and gaseous hazards?
Hazardous chemicals that are flammable, volatile, or gases should be manipulated
inside a properly functioning chemical fume hood. Use of these materials on the
open bench may lead to hazardous exposures or allow vapor concentrations to
reach flammable proportions. [Prudent Practices in the Laboratory p. 95-96]
3. Are fume hoods free of excess storage?
While it is appropriate to keep chemicals that are being used during a
particular experiment inside the fume hood, hoods are not designed for permanent
chemical storage. Using a fume hood for storage can severely compromise
its ability to capture contaminants. Each item placed on the work surface
interferes with the directional air flow, causing turbulence and eddy currents
that allow contaminants to be drawn out of the hood. [Prudent Practices in the
Laboratory p. 180]
4. Are large pieces of equipment raised to allow air flow?
Essential to the efficient operation of the hood is the laminar airflow that
sweeps across the working surface of the hood. Large pieces of equipment such as
ovens or water baths placed directly onto the hood surface will block this route
of air flow, causing turbulence and loss of containment. By elevating equipment
a few inches off the floor of the hood, we can maintain the sweeping properties
of the airflow and minimize turbulent interference. [Prudent Practices in the
Laboratory p. 179]
5. Are procedures conducted at least 6" inside hood?
The area immediately inside the hood entrance is one of turbulent air flow.
Additionally, when a person stands in front of the hood a triangular area of
negative pressure extends out from the body into the hood. Substances released
in the turbulent or negative pressure regions are not well contained and can
escape from the hood, thus entering the worker’s breathing zone and adding to
their exposure. By conducting all procedures at least 6 inches inside the hood,
fugitive exposures can be minimized. [Prudent Practices in the Laboratory p.
6. Is there a visual indicator of hood flow? (gauge, ribbon)
Hoods can malfunction without warning. Consequently, it is important to confirm
hood operation before each work session. Check the air flow gauge, if so
equipped. In the absence of a gauge, you can tape an inch wide strip of tissue
to the lower corner of the sash. Air flow can be visually assessed by noting
that the tissue is pulled gently into the hood. Never work with a malfunctioning
hood; report problem hoods to Work Control at 742-3301. [OSHA 29CFR 1910.1450
(e) (3) (iii); Prudent Practices in the Laboratory p. 180]
7. Is the fume hood sash lowered to or below optimum setting?
Optimum height is the sash height at which air flow is maximized without
creating turbulence, generally 100 feet per minute. A red sticker placed on the
hood face indicates the most recently recommended sash height. With unattended
or potentially explosive processes, use a lowered sash as a barricade behind
which to conduct the procedure. [Prudent Practices in the Laboratory p. 179,
8. Are perchloric acid hoods utilized whenever perchloric acid is heated?
Perchloric acid, when heated for digestions (or any other purpose), must be used
in a fume hood specially designed for that purpose. These fume hoods are
typically clearly labeled by the manufacturer as a “Perchloric Acid Hood,” and
any event will be equipped with a wash-down unit. The wash-down unit rinses the
innards of the hood, including baffles and other inner surfaces, with water to
prevent the buildup of potentially explosive reactive perchlorate salts on fume
9. Are tissue culture hoods (i.e., non-biosafety cabinets) used for nonhazardous
materials only; with chemical and biological hazards prohibited?
Tissue culture hoods (a.k.a. laminar flow hoods) bathe the product and work
surface in particulate free air. Unlike a biosafety cabinet, there are no
safeguards that serve to contain hazards within the cabinet. Consequently, these
hoods offer product protection only; the user and laboratory environment are
readily exposed to hazards agents found in the hood. [CDC/NIH Primary
Containment for Biohazards: Selection, Installation and Use of Biological Safety
Cabinets p. 13]
10. In biosafety cabinets, are volatile or gaseous hazards limited to incidental
Small amounts of volatile chemicals can be used in biosafety cabinets that
exhaust outside the building. Because of recirculation patterns and other air
flow characteristics, significant quantities of hazardous gases or vapors will
not be efficiently removed and can present a toxic or fire hazard. Remember,
biosafety cabinets do not function as and cannot be substituted for chemical
fume hoods. Any procedure necessitating the use of significant amounts of
volatile or gaseous hazards must be conducted inside a functioning chemical fume
hood. [CDC/NIH Primary Containment for Biohazards: Selection, Installation and
Use of Biological Safety Cabinets p. 15, 35]
E. Compressed Gases
1. Are cylinders properly secured?
Compressed gas cylinders are under great pressures, often exceeding 2000 pounds
per square inch or 136 atmospheres. To prevent the accidental and uncontrolled
release of energy it is important to protect cylinders from toppling over and
rupturing the valve stem. All compressed gas cylinders, including lecture
bottles, “empty” cylinders, and cylinders in transit, must be secured in racks,
clamping devices, holders, stands, or other protective structure. [Prudent
Practices in the Laboratory p. 122; Guide to Safe Handling of Compressed Gases
2. Are cylinders capped when not in use?
The most vulnerable spot of a compressed gas cylinder is the valve stem.
Accidental dislocation can result in a sudden and violent release of the
cylinder contents. Consistently replacing the cap when the cylinder is not
in use protects the valve stem from damage, even if the cylinder should topple
over. [Prudent Practices in the Laboratory p. 122; Guide to Safe Handling of
Compressed Gases p. 70]
3. Are main valves closed and the pressure in regulators released when the
cylinder is not in use?
The cylinder valve should never be left open when the equipment is not in use,
even if the cylinder is “empty”. An open valve can allow air, moisture and other
contaminants into the cylinder as it “breathes” during temperature changes. This
can result in an explosive mixture if the gas is flammable or severe corrosion
if the cylinder contains a corrosive gas. [Prudent Practices in the Laboratory
p. 122; Guide to Safe Handling of Compressed Gases p. 76]
5. Are flammable gases present only where there is ongoing use?
In addition to the pressure hazards of the cylinder itself, flammable gases are
also extreme fire and explosion hazards. Consequently it is prudent to reduce
their presence to only that which is necessary. Only those labs that have an
ongoing or routine need should store flammable gases. Cylinders that are no
longer needed should be promptly returned to the supplier.
7. Are flammable gases separated from oxidizing gases?
Separating flammable and oxidizing gases by distance, wall or partition reduces
the risk of developing a flammable or explosive situation. Since the range of
flammability increases in the presence of an oxidizer, these gases in close
proximity are particularly hazardous. [Prudent Practices in the Laboratory p.
124; Guide to Safe Handling of Compressed Gases p. 24]
F. Work Practices
1. Are food and drink never stored or consumed in the lab?
Food and drink brought into areas of chemical, biological or radiological use
can easily become contaminated by these hazards. Airborne particulates can
settle on exposed food, eating surfaces or utensils. Even though work surface
contamination may not be readily apparent, it can adhere to hands and then be
transferred to food items. Upon ingestion these harmful substances will be
carried into the body, increasing the opportunity for toxic effects.
Eating, drinking, smoking, gum chewing, applying cosmetics, and taking medicine
in laboratories where hazardous materials are used should be strictly
prohibited. Food, beverages, cups, and other drinking and eating utensils should
not be stored in areas where hazardous materials are handled or stored.
Glassware used for laboratory operations should never be used to prepare or
consume food or beverages. Laboratory refrigerators, ice chests, cold rooms,
ovens, and so forth should not be used for food storage or preparation.
[OSHA 29CFR 1910.141 (g) (2), (g) (4)]
2. Is proper lab attire worn?(no shorts, sandals, loose hair or loose clothing)
Street clothing worn in the laboratory provides a barrier function, protecting
skin from contact with hazardous chemicals. Clothing that leaves large areas of
skin exposed is inappropriate where hazardous chemicals are in use. Long pants
and shoes that enclose the entire foot will delay hazardous actions of chemicals
spilled onto those areas. Consequently, sandals, shorts, short skirts, and
open toed shoes should never be worn in the laboratory. Loose hair and clothing
can become entangled in machinery or can dip into hazardous materials. [OSHA
29CFR 1910.132 (a), (d); Prudent Practices in the Laboratory p. 83, 131]
3. Is mouth pipetting prohibited?
Although once commonly practiced, mouth pipetting has become a rarity due to the
availability and ease of use of pipetting devices. Principal Investigators are
reminded to reinforce the mouth pipetting prohibition with entering students,
especially since not all international students will have received this
instruction prior to coming to the University. [OSHA 29CFR 1910.1030 (d) (2)
4. Are needles and other sharps disposed of in a labeled, color coded, puncture
According to the OSHA Bloodborne Pathogens Standard, contaminated sharps include
needles, scalpels, broken capillary tubes, exposed dental wires, and broken
glass if contaminated with human blood or other potentially infectious material.
These items must be collected in a sharps box or other puncture resistant
container that is color coded or labeled with the universal biohazard symbol.
[OSHA 29CFR 1910.1030 (b), (d)(2)(viii)]
5. Are sharps containers not overfilled?
Sharps containers must be sealed before being placed into the infectious waste
stream. Not uncommonly, sharps boxes are allowed to fill completely before
securing the lid. As the lid is closed, these closely confined items can shift
position and protrude from the container, increasing the risk of an accidental
needlestick injury. A good rule of thumb to avoid inadvertent overfilling is to
seal and dispose of the container when it is 3/4 full. [OSHA 29CFR
1910.1030 (d) (4) (iii) (A) (2) (iii)]
6. Are ignition sources prohibited where flammable chemicals used or stored?
One of the easiest methods of fire risk reduction is to remove ignition sources
from a flammable system (fuel + oxygen + ignition source). Ignition sources
include electrical outlets, lighting fixtures, switches, exposed machinery
components, as well as open flame. Flammable solvents should be used inside a
chemical fume hood so vapors will be prevented from reaching flammable
proportions. In the special case of a flammable solvent being heated (as in a
distillation) it is important that all ignition sources (electrical outlets,
Variac controllers, outlet strips) be located to the outside of the hood. [NFPA
45 9-1.2.1, 9-2.3.3; Prudent Practices in the Laboratory p. 95-96]
7. Are dewar flasks and cold traps wrapped with screen, friction tape, or a
Dewar flasks are under high vacuum and can collapse as a result of thermal or
very slight mechanical shock. To prevent shards of glass from being propelled
throughout the lab in the event of breakage, Dewars should be shielded with
friction tape or enclosed in a wooden or metal container. [NFPA 45 9-1.6.1;
Prudent Practices in the Laboratory p. 130]
8. Are closed systems under heat or pressure contained behind a blast shield or
in a fume hood with the sash lowered?
Closed systems under heat or pressure, either externally applied or due to
internal changes in the system, are at risk of explosion. To protect lab
occupants these systems should be protected by blast shields configured to cover
all sides, or conducted inside a chemical fume hood with the sash lowered so as
to act as a shield. [NFPA 45 9-1.6.1; Prudent Practices in the Laboratory p.
9. Are pulleys, belts and other moving parts properly guarded?
Some common pieces of lab equipment present physical hazards due to rotating
parts, nip points or other mechanical action. Particularly prevalent in the lab
are vacuum pumps that have had their belt guards removed. To prevent injury due
to entrapment of hair, clothing or other items it is necessary that these areas
remain guarded. Any piece of equipment with a detached, disengaged or inoperable
guard must be prominently tagged and removed from service. [OSHA 29CFR 1910.212;
Prudent Practices in the Laboratory p. 120]
10. Are vacuum lines equipped with traps?
Protect vacuum pumps and lines against contamination with traps and/or
appropriate filters and vent effluent into the chemical fume hood. Also, empty
traps prior to becoming full to avoid spills and contamination of vacuum lines.
G. Electrical Hazards
1. Are electrical cords and plugs intact; not damaged or frayed?
Any break in the integrity of an electrical cord’s insulation can allow moisture
to seep in or the conductor to contact metal with the possibility of painful
shock. All frayed or damaged cords must be completely replaced before the
equipment is allowed back into use, or the item disposed of. Replacement plugs
must fully encase the primary and secondary insulation. [OSHA 29CFR 1910.303
(c); Prudent Practices in the Laboratory p. 110]
2. Are electrical cords free of tape splices or repairs?
Contrary to popular belief, electrical cords spliced with electrical tape are
significantly less protective than an intact cord. Electrical tape is not a good
insulator and will not check current flow. Cord splices and repairs should be
made by qualified personnel using techniques that retain the insulation, outer
sheath properties and usage characteristics properties of the cord. [OSHA 29CFR
1910.305 (g)(2)(ii); OSHA 29CFR 1910.303 (c)]
3. Is no more than one item plugged into an individual receptacle?
Multi-outlet adapters and octopus extenders can overload and short-circuit.
Power strips with an integrated circuit breaker are designed to handle the
excess current load and can be safety used when additional outlets are needed.
4. Are extension cords used on a temporary basis only, not as a permanent source
Extension cords can be used for short duration, temporary purposes only. If
additional outlets are needed on a long term or routine basis then they must be
permanently installed by a qualified person. [OSHA 29CFR 1910.305
(g)(1)(iii)(A); Prudent Practices in the Laboratory p. 110]
5. Are grounded or polarized plugs unaltered?
Equipment supplied with a grounded plug require attachment to a ground source.
Removal of the grounding prong interferes with this electrical safety feature
and can result in shock or electrocution. [OSHA 29CFR 1910.334 (a)(3)(ii)]
H. Emergency Equipment/Fire Safety
1. Are exits and means of egress unlocked and unobstructed?
It is best if every laboratory have two unobstructed means of egress available
at all times. An accident such as a fire or large chemical spill occurring
near the main lab entrance blocks that possible exit. In such an event a
secondary means of egress (such as into an adjoining laboratory) can be used to
safely evacuate the lab. To ensure the availability of an exit in the event of
an emergency it is important that doors can be opened without undue burden
(unlocked), and that there are no obstructions that might hinder escape such as
carts or furniture blocking the door. [OSHA 29CFR 1910. 37 (f) (3); Prudent
Practices in the Laboratory p. 84]
2. Is an eighteen inch vertical clearance maintained from sprinkler heads (e.g.,
Combustible materials were stored within 18 inches from the ceiling. All
combustible material should be stored below 18 inches from the ceiling to ensure
optimal fire sprinkler coverage, if present, and to comply with the State of
Texas Fire Codes.
5. Are safety showers/eyewashes clearly visible and unobstructed?
Immediate access to a safety shower/eyewash is necessary to avoid permanent
damage should a chemical be splashed onto the face, eyes or body. Storing carts
or other items underneath a safety shower/eyewash makes it inaccessible in the
event of an emergency. The extra time needed to relocate items or navigate
obstacles in order to gain access to a safety shower or eyewash can mean the
difference between a mild chemical irritation and corneal perforation. [Prudent
Practices in the Laboratory p. 133]
7. Does lab staff know the location of emergency equipment?
Laboratory personnel must know what to do in case of an emergency. The locations
of all emergency equipment (safety shower, eyewash, fire extinguisher, emergency
exits) should be memorized and workers able to retrieve or reach them
immediately, without wasting valuable seconds thinking about it. Since a
chemical splash to the eyes effectively blinds a person, be prepared to find the
eyewash without assistance should the need arise. [Prudent Practices in the
Laboratory p. 87]
I. Chemical Handling and Storage Safety
1. Are all chemicals color-coded and segregated by hazard class?
Chemicals should be color-coded according to the J.T. Baker color coding system,
using colored tape. This should be done upon receipt of the chemical.
Information on the JT Baker color-coding system can be found in the University
Chemical Hygiene Plan. Additionally, chemicals should be segregated by
hazard class, and stored on separate shelves or within separate cabinets, as
necessary, to prevent reactivity issues that may arise. This is especially
important when dealing with concentrated acids, bases, toxic compounds,
oxidizers, and other reactive compounds. Lastly, organic and inorganic
chemicals should be segregated and stored appropriately on separate shelves or
cabinets to prevent reactivity issues that may arise.
2. Is solvent usage limited to the fume hood, or another area equipped with
local exhaust? Are other chemicals (such as acrylamide) that pose serious
respiratory hazards used exclusively in the fume hood?
Solvents, whether organic or inorganic, are frequently capable of posing
respiratory hazards when they are improperly used. Acute health effects include
nausea, headaches, fatigue, vomiting, difficulty breathing. Chronic effects
include CNS damage, cardiovascular and respiratory system dysfunction, cancer,
and, in extreme cases, death. These effects may occur as solvent vapors are
inhaled when solvents are opened or used in areas without adequate ventilation.
Fume hoods are necessary to exhaust harmful solvent vapors away from the
employee, thus creating a safe work environment. Certain liquid and solid
chemicals, besides solvents, are capable of causing health effects listed above
when inhaled. This includes chemicals such as solid acrylamide or methylated
transition metals (e.g., trimethylzinc) that are of a respirable particle size.
These chemicals must never be used or manipulated outside the fume hood, for the
same reasons listed above.
3. When present, are hydrofluoric, nitric, and perchloric acids stored properly?
When these acids are present in a lab, unique hazards are posed to the employees
working with them. Nitric, hydrofluoric, and perchloric acids must always be
stored in secondary containment trays, made of chemically-resistant material
(HDPE, Teflon) designed for this purpose. The only exception to the need for
secondary containment occurs when these acids are stored separate from all other
compounds, including other inorganic acids. Under no circumstances should these
chemicals be stored in the same cabinet with anything other than concentrated
inorganic acids, with or without secondary containment.
4. Are hydrofluoric acid (HF) safety procedures posted and observed? Are first
aid procedures and fresh calcium gluconate gel available?
Hydrofluoric acid poses exposure hazards that most other acids do not. In
addition to being corrosive, the fluoride ion in HF is highly toxic. As such, HF
is highly toxic through both inhalation of fumes and skin contact. Fluoride
toxicity includes acute effects such as CNS and respiratory system dysfunction;
in large doses death may result. It is therefore important to have quick access
to HF safety and first aid procedures; these should be posted in a prominent
area within the lab. HF safety and first aid procedures are available through
the Chemical and Biological Safety Officer, who can be contacted at 742.3876.
Calcium gluconate gel, a key component of first aid for HF exposure victims,
must be kept on hand in all labs that use HF in any amount. Since it expires
within one year of receipt, it must be reordered on an annual basis to ensure
its efficacy in the event of an HF exposure.
5. Are procedures involving heated perchloric acid prohibited except in a
perchloric acid hood?
When heated, perchloric acid will evolve substantial amounts of acid vapors that
can condense inside the fume hood exhaust system. The condensed acid is then
free to react with organics present in the area (such as litharge-glycerin
cement frequently found in duct work) to form extremely powerful,
shock-sensitive perchlorate salts and esters. Because of the ease with
which these materials can be formed in a chemical fume hood exhaust system and
the devastating results of hood system explosions, heated perchloric acid can
safely be used only in a perchloric acid fume hood with wash-down provisions.
Unfortunately, at this time there are only a few of these hoods on the Texas
Tech campus that are fully equipped to handle heated perchloric acid. [Prudent
Practices in the Laboratory p. 103, 187]
6. When present, are acids and bases stored on separate shelves or cabinets?
Acids and bases, when combined, produce vigorous reactions capable of generating
toxic gases, heat, and pressure, depending on the circumstances. These chemicals
should be segregated on separate shelves within the same cabinet, at a minimum.
This will prevent accidental combination leading to vigorous reactions.
7. Is picric acid stored hydrated at all times? Is an appropriate usage log
Picric acid is used in staining procedures, and occasionally in synthesis
reactions. When hydrated, it is typically harmless. However, it is a precursor
to TNT formation, and is itself a powerful shock-sensitive explosive when the
crystals are desiccated. Because of this fact, picric acid must be stored
hydrated, preferably under a visible standing film of water, at all times. The
inside surface of the lid to the picric acid storage container should be rinsed
with deionized water after each time the container is opened. Further, a
usage log must be maintained that lists each occasion, by date, that the picric
acid is opened, for any reason. The log should have entries for user initials,
and a checkbox where the user can verify that he/she has rinsed the lid and
rehydrated the picric acid, as necessary. In this fashion, all employees in the
lab who work with picric acid can be assured of a safe work experience each time
it is used.
8. Are all flammable chemicals stored in approved flammable chemical storage
Fires are the most frequent of catastrophic accidents in laboratory settings.
Flammable storage cabinets are essential to provide both adequate storage space
and personnel protection. All chemicals having an NFPA flammability rating of 2
or greater must be stored in flammable storage cabinets. In labs that are not
equipped with built-in flammable storage casework, the red or yellow packaged
flammable storage cabinets should be purchased and utilized as much as possible.
Flammable chemicals must NEVER be stored on the floor, on open shelves, or in
fume hoods, as all three of these locations increase the likelihood of chemical
spills leading to fire.
9. Flammable liquids are not stored in conventional refrigerators?
A number of common solvents have flashpoints close to or below the temperature
at which most refrigerators operate (around 38°F, 3°C). Flammable solvents
evaporate rapidly even at low temperatures; they can quickly reach equilibrium
inside the small, well-sealed space of a refrigerator. When flammable vapors
reach the lower explosive limit concentration (%LEL), sources of ignition inside
a conventional refrigerator such as the thermostat, interior light, defroster,
compressor, or fan can set off an explosion. This is especially dangerous in the
case of very low flashpoint solvents such as ethyl ether. Flammable liquids that
must be stored at reduced temperature require a specially designed refrigerator,
termed a “flammable material storage refrigerator” or “explosion-proof
refrigerator,” where ignition sources are isolated from the inside space.
10. Is the total flammable chemical storage limited to 75 gallons in
instructional labs and 150 gallons for research labs?
With the exception of chemical storage rooms designed for flammable storage, all
research labs must limit flammable chemical storage to 150 gallons or less. With
the exception of chemical storage rooms designed for flammable storage, all
instructional labs must limit flammable chemical storage to 75 gallons or less.
These limits are part of the state fire code to which all public places must
adhere in the state of Texas.
11. Are chemicals stored away from heat and intense light sources?
Hazardous chemicals, especially those that are flammable or highly reactive,
must NEVER be stored near heat sources (such as incubators, ovens, GCs,).
Chemicals should also be stored away from intense light sources, where
applicable. This prevents sudden fire and reactivity hazards that may arise.
These precautions, when observed, will also serve to lengthen the shelf life for
many reagents that are marginally heat-labile or photosensitive. In any event,
all chemicals should be stored in cabinets or on open shelving, segregated and
stored as appropriate for the hazard classification of the chemicals in
12. Are chemical containers in good condition? Are labels present and legible?
Chemical containers should not be corroded or cracked in any way, to prevent
accidental exposures or spills. Labels should be clearly legible, and should
clearly state the following information.
a. name of chemical, and concentration, where pertinent (such as weight/weight%
b. date received, and/or expiration date, where applicable
c. owner’s initials, if multiple personnel use the lab space
d. hazard identification information, such as NFPA labeling
13. Are large chemical containers stored near the floor?
Large chemical containers, such as those weighing 5kg or more, or those
containing 15 liters or more, should be stored near the floor to prevent
14. Are bottle carriers and/or transportation carts utilized when moving
chemicals from one room to another?
When lab employees move hazardous chemicals between different rooms, the
potential increases for chemical spills due to tripping, bumping, etc. Rubber
chemical carriers, designed for cradling glass four-liter chemical containers,
can minimize the risks associated with transporting chemicals between rooms.
Whenever a principal investigator supervises work in two or more rooms, rubber
chemical carriers or transportation carts should be made available in at least
one room; in this fashion all employees will have access to a means of safe
15. Are peroxides and peroxide-forming compounds labeled with receipt date
and/or expiration date? Are any peroxide or peroxide-forming compounds present
that are expired?
Peroxides and peroxide-forming compounds (i.e., ethers, THF, dioxane, many
others) undergo auto-oxidation to spontaneously form organic peroxides that are
more shock sensitive than TNT and other conventional explosives. Especially
dangerous are ether bottles that have evaporated to dryness. By labeling the
containers with date received, date opened, and/or expiration date, these
chemicals can be disposed of within a safe time frame before peroxide formation
has progressed to dangerous levels. [NFPA 45 7-2.3.5] Once the printed
expiration date for a peroxide or peroxide-forming chemical has been reached,
the chemical can simply be submitted for disposal or tested for peroxides. If no
expiration date is printed on the bottle, then the chemical should be disposed
or tested for peroxides after one year from the receipt date. As long as the
peroxide test strip continues to read negative, new expiration dates can be
J. Special Procedures for Carcinogens, Teratogens, and Other Highly Toxic
1. Are designated work areas for these compounds present wherever these
chemicals are used? Are designated work areas clearly labeled, utilized, and
An area (or areas) in the lab that affords maximum personal protection, such as
the fume hood, must be designated with a visible sign as the exclusive area(s)
of use for carcinogens and other highly toxic compounds. Highly toxic compounds
are those chemicals having an LD50 (lethal dose for 50% of the given test
population) in a given animal population of less than 50 mg/kg body weight by
any exposure route. It is important to clearly designate the work area(s) so
that a visual reminder is present for each employee that commands their
attention. This encourages the use of PPE and other safe work practices.
Additionally, please ensure that workbenches are appropriately decontaminated
when work is performed outside the fume hood (for example, when performing gel
electrophoresis with ethidium bromide-treated gels).
2. Have adequate written procedures been created for the use of these compounds?
Have employees received training specific to work with these classes of
The following information should be presented to new and current employees
concerning all carcinogens, mutagens, and teratogens present in these labs:
a. Introduction to the University Chemical Hygiene Plan
b. Physical and health hazards presented by chemicals, procedures, and equipment
present in the work environment
c. Specific measures employees should take to protect themselves and others,
including the proper application and use of personal protective equipment (PPE)
d. Types and classes of hazardous chemicals present
e. Introduction to MSDS, emergency response procedures, chemical spill safety
f. Any other work-specific, safety-related information that would be conducive
to producing a safe work environment
See the University Chemical Hygiene Plan, Appendix I-1, (online at EH&S website
at http://www.ehs.ttu.edu/CHEMPLN.pdf) for further assistance in creating
written procedures related to the storage and use of compounds that are
considered to be carcinogens, mutagens, or teratogens, or otherwise highly toxic
J. Hazardous Waste Compliance
1. Are waste containers labeled using the content of the waste with complete
All hazardous chemical waste containers should be labeled with the contents of
the waste material. For example, a label identifying a waste container as
organic waste is not an appropriate label. The waste container must be labeled
with the complete chemical names identifying the contents of the waste material.
2. Are waste containers in good condition and kept closed except when adding
Hazardous chemical waste must be managed in containers that are in good
condition, of compatible materials, and kept loosely-capped, except when adding
waste to the container.
3. Is chemical waste disposed down the sink or in regular waste bins?
All chemical waste must be treated as hazardous waste, for the purposes of waste
disposal. Even when the waste is something relatively benign like alumina gel or
magnesium sulfate column packing, this recommendation should be observed.
Unfortunately, our custodial staff cannot be expected to know the difference
between hazardous and non-hazardous chemical waste by sight. By storing and
labeling all chemical waste as hazardous waste, including column packing,
secondary products such as precipitates, and rinse solvents, we can both comply
with applicable hazardous waste laws and ensure that our custodial staff is
4. Are wastes properly segregated?
All waste material must be properly segregated for disposal. Do not mix chemical
waste with radioactive waste or biological waste. If your laboratory generates
several types of hazardous waste, use separate containers for each type unless
specifically approved by EH&S. This allows for use of the best disposal options
and prevents potential hazards due to chemical incompatibilities.
5. Are lab waste accumulation areas belonging to the PI located near the point
of initial generation of the waste and is the waste under the control of the lab
personnel that generated the waste?
All hazardous waste must be accumulated at or near the point of initial
generation and must be under the control of the operator of the process
generating the waste. EH&S should be contacted at 742.3876 for hazardous waste
pickup and disposal.