Chapter 7 - Safe Chemical UseChapter 7 - Safe Chemical Use
Safe chemical use includes minimizing exposure to chemicals, proper training, understanding chemical hazards, proper labeling, proper storage and segregation, and proper transport.
- OSHA Lab Standard
- OSHA Permissible Exposure Limits Topics Webpage
- OSHA Definition of Physical Hazard
- EHS Training Webpage
- EHS Signs and Labels webpage
- Safety Data Sheets Webpage
- SDS Hyperglossary
- HMIG and HMIS
- Safety in Academic Chemistry Laboratories
- Department of Transportation (DOT) hazard class system
- OSHA Toxic and Hazardous Substances
- OSHA Definition of Health Hazard
- University Health and Safety Policy
- EHS Online Training Programs
- EHS Right-To-Know Chemical Labels
- SDS FAQ
- NFPA diamond
- OSHA SDS Form 174
- Prudent Practices in the Laboratory
- DOT training Modules
- Department of Transportation (DOT) hazard class system
7.1 Minimize Exposure to Chemicals7.1 Minimize Exposure to Chemicals
The best way laboratory personnel can protect themselves from chemical hazards is to minimize their exposure to them. In order to minimize chemical exposure:
- Substitute less hazardous chemicals in your experiments whenever possible.
- Always use the smallest possible quantity of chemical for all experiments. Consider microscale experiments and activities.
- Minimize chemical exposures to all potential routes of entry - inhalation, ingestion, skin and eye absorption, and injection through proper use of engineering controls and personal protective equipment.
- Be sure to select the proper PPE and regularly inspect it for contamination, leaks, cracks, and holes. Pay particular attention to gloves.
- Do not pipette or apply suction by mouth.
- Do not smell or taste chemicals. When it is necessary to identify a chemical’s odor, lab personnel should hold the chemical container away from their face and gently waft their hand over the container without inhaling large quantities of chemical vapor.
- Do not underestimate the risk of exposure to chemicals - even for substances of no known significant hazard.
- In order to identify potential hazards, laboratory personnel should plan out their experiments in advance. These plans should include the specific measures that will be taken to minimize exposure to all chemicals to be used, the proper positioning of equipment, and the organization of dry runs.
- Chemicals that are particularly hazardous substances require prior approval from your supervisor and special precautions to be taken.
- When working with mixtures of chemicals, laboratory personnel should assume the mixture to be more toxic than the most toxic component in the mixture.
- Consider all substances of unknown toxicity to be toxic until proven otherwise.
- Request exposure monitoring to ensure the Permissible Exposure Limits (PELs) of OSHA and the current Threshold Limit Values (TLVs) of the American Conference of Governmental Industrial Hygienists are not exceeded.
- Promptly clean up all chemicals spills regardless whether the chemical is considered hazardous or nonhazardous. When cleaning up spills, remember to clean up any splashes that may have occurred on the sides of cabinets and doors in the immediate area.
- When working in cold rooms, keep all toxic and flammable substances tightly closed as cold rooms have recirculated atmospheres.
- Be aware of the potential asphyxiation hazard when using cryogenic materials and compressed gases in confined areas such as cold rooms and environmental chambers. If necessary, install an oxygen monitor/oxygen deficiency alarm and/or toxic gas monitor before working with these materials in confined areas. Contact EHS at 607-255-8200 for more assistance.
- Do not eat, drink, chew gum, or apply cosmetics in areas where hazardous chemicals are being used.
- Keep all food and drink out of refrigerators and freezers used to store chemicals. Refrigerators used to store chemicals should be labeled as “Chemicals Only – No Food”. Refrigerators used to store food should be labeled as “Food Only – No Chemicals”. You can download these and other free labels at the EHS Signs and Labels webpage.
- Always wash hands with soap and water after handling chemicals and especially before leaving the lab and eating – even if gloves were worn during chemical handling.
- Always remove personal protective equipment, such as gloves and lab coats, before leaving the lab.
- Do not attempt to scale up experiments until after you have run the experiment according to published protocols and you are thoroughly familiar with the potential hazards. When scaling up an experiment – change only one variable at a time, i.e. don’t change the heat source, the volumes, and the glassware all at once. It is also advisable to let one of your other lab group members to check your setup prior to each run.
7.2 Understanding Chemical Hazards7.2 Understanding Chemical Hazards
Chemicals pose both health and physical hazards. For the purposes of this document, health hazard will be used interchangeably with chemical hazard and health effects on the body will be used interchangeably with chemical effects on the body.
According to OSHA, health hazard means “a chemical for which there is statistically significant evidence based on at least one study conducted in accordance with established scientific principles that acute or chronic health effects may occur in exposed employees. The term ‘health hazard’ includes chemicals which are carcinogens, toxic or highly toxic agents, reproductive toxins, irritants, corrosives, sensitizers, hepatotoxins, nephrotoxins, neurotoxins, agents which act on the hematopoietic system and agents which damage the lungs, skin, eyes, or mucous membranes.”
According to OSHA, physical hazard means “a chemical for which there is scientifically valid evidence that it is a combustible liquid, a compressed gas, explosive, flammable, an organic peroxide, an oxidizer, pyrophoric, unstable (reactive) or water-reactive.” Physical hazards are covered in other sections within this manual.
7.2.1 Chemical Hazard Information7.2.1 Chemical Hazard Information
As part of the employers Chemical Hygiene Plan, the OSHA Laboratory Standard requires that “the employer shall provide employees with information and training to ensure that they are apprised of the hazards of chemicals present in their work area…Such information shall be provided at the time of an employee’s initial assignment to a work area where hazardous chemicals are present and prior to assignments involving new exposure situations.”
- This Laboratory Safety Manual
- Known reference materials (EHS maintains a reference library)
- Training videos (EHS maintains a video library available for loan)
- Other department’s safety manuals
- Safety Data Sheets (SDSs)
- EHS Training Programs
- Departmental Safety Committees
- Container labels
- Laboratory Standard Operating Procedures
- Laboratory signage and postings
- Publications such as the American Chemical Society – Safety in Academic Chemistry Laboratories
7.3 Safety Data Sheets7.3 Safety Data Sheets
Safety Data Sheets (SDSs) are an important part of any laboratory safety program in communicating information to chemical users. SDSs provide useful information such as:
- The identity of the chemical substance.
- Physical and chemical characteristics.
- Physical and health hazards.
- Primary routes of entry.
- OSHA Permissible Exposure Limits (PELs).
- Carcinogenic and reproductive health status.
- Precautions for safe handling and use (including PPE).
- Spill response procedures.
- Emergency and first aid questions.
- Date the SDS was prepared.
- Any chemical shipment received should be accompanied by an SDS (unless one has been shipped with a previous order). If you do not receive an SDS with your shipment, check the chemical manufacturers website first (or call the manufacturer directly), or check the EHS SDS website for links to SDSs, or contact EHS at 607-255-8200 to request assistance in obtaining the SDS.
If you have questions on how to read SDSs, or questions about the terminology or data used in SDSs, you can contact EHS at 607-255-8200 for more information. Additional information, including how to read an SDS, can be found in the SDS FAQ and a glossary of terms used on SDSs can be found in the “Hyperglossary”. Information on the National Fire Protection Association - NFPA diamond and the Hazardous Materials Information Guide and Hazardous Materials Information System – HMIG and HMIS - is also available.
SDSs must be accessible at all times. Access to SDSs can mean access to paper copies or electronic access via the internet. EHS maintains links to a number of SDS websites and other sites with chemical health and safety information.
EHS strongly encourages paper copies of SDSs be kept in the laboratory, however, having SDS websites bookmarked is acceptable as long as all employees in the workplace know where to find the SDSs and are trained on the use of computers to access SDSs. If a laboratory chooses to use electronic access, then EHS recommends the SDS website link be posted on the computer or in another conspicuous location. Some departments maintain three ring binders - “Big Red Books” - with SDSs. Check with your DSR for the location of the departmental SDS collection.
7.3.1 SDSs and Newly Synthesized Chemicals7.3.1 SDSs and Newly Synthesized Chemicals
Principal Investigators will be responsible for ensuring that newly synthesized chemicals are used exclusively within their laboratories and are properly labeled. If the hazards of a chemical synthesized in the laboratory are unknown, then the chemical must be assumed to be hazardous and the label should indicate the potential hazards of that substance have not been tested and are unknown.
The Principal Investigator must ensure a SDS is prepared for newly synthesized chemicals if:
- The chemical is hazardous according to the OSHA definition of hazardous (if the hazards are not known, then the chemical must be assumed to be hazardous).
- The newly created chemical or intermediate compound is going to be transferred to a different researcher or testing lab on or off of the Cornell University campus.
- The newly created chemical or intermediate compound is going to be kept in the lab for an on-going basis for use by current and/or future researchers in the lab where it was originally made.
- The newly created chemical or intermediate compound is going to be provided to another research group at Cornell University.
Additional information on developing SDSs can be found in the SDS FAQ. A blank SDS form (OSHA Form 174) can be found on the OSHA website. A description of how to fill out an SDS can be found in the appendix.
7.4 Routes of Chemical Entry7.4 Routes of Chemical Entry
The potential health effects that may result from exposure to chemicals depends on a number of factors. These factors include the properties of the specific chemical (including toxicity), the dose and concentration of the chemical, the route of exposure, duration of exposure, individual susceptibility, and any other effects resulting from mixtures with other chemicals.
In order to understand how chemical hazards can affect you, it is important to first understand how chemicals can get into your body and do damage. The four main routes of entry are inhalation, ingestion, injection, and absorption through the skin and eyes.
7.4.1 Inhalation7.4.1 Inhalation
Inhalation of chemicals occurs by absorption of chemicals via the respiratory tract (lungs). Once chemicals have entered into the respiratory tract, the chemicals can then be absorbed into the bloodstream for distribution throughout the body. Chemicals can be inhaled in the form of vapors, fumes, mists, aerosols and fine dust.
Symptoms of exposure to chemicals through inhalation include eye, nose, and throat irritation, coughing, difficulty in breathing, headache, dizziness, confusion, and collapse. If any of these symptoms are noted, leave the area immediately and get fresh air. Seek medical attention if symptoms persist and complete and Injury/Illness Report.
Laboratory workers can protect themselves from chemical exposure via inhalation through proper use of a functioning fume hood, use of dust masks and respirators when a fume hood is not available, avoiding bench top use of hazardous chemicals, ensuring chemical containers are kept tightly capped, and ensuring all chemical spills are promptly cleaned up.
7.4.2 Ingestion7.4.2 Ingestion
Chemical exposure through ingestion occurs by absorption of chemicals through the digestive tract. Ingestion of chemicals can occur directly and indirectly. Direct ingestion can occur by accidently eating or drinking a chemical; with proper housekeeping and labeling, this is less likely to occur. A higher probability of receiving a chemical exposure can occur by way of indirect ingestion. This can occur when food or drink is brought into a chemical laboratory. The food or drink can then absorb chemical contaminants (vapors or dusts) in the air and result in a chemical exposure when the food or drink is consumed. This can also occur when food or drink is stored with chemicals, such as in a refrigerator. Ingestion can occur when a laboratory worker who handles chemicals does not wear gloves or practice good personal hygiene, such as frequent hand washing, and then leaves the laboratory to eat, drink, or smoke. In all cases, a chemical exposure can result, although the effects of chronic exposure may not manifest itself until years later.
Symptoms of chemical exposure through ingestion include metallic or other strange tastes in the mouth, stomach discomfort, vomiting, problems swallowing, and a general ill feeling.
After seeking medical attention, complete an Injury/Illness Report.
The best protection against ingestion of chemicals is to properly label all chemical containers, never consume food or drink or chew gum in laboratories, always wear PPE (such as gloves), and practice good personal hygiene, such as frequent hand washing.
7.4.3 Injection7.4.3 Injection
Chemical exposure via injection can occur when handling chemically contaminated items such as broken glass, plastic, pipettes, needles, razor blades, or other items capable of causing punctures, cuts, or abrasions to the skin. When this occurs, chemicals can be injected directly into the bloodstream and cause damage to tissue and organs. Due to direct injection into the bloodstream, symptoms from chemical exposure may occur immediately.
Laboratory workers can protect themselves from an injection hazard by wearing proper PPE such as safety glasses/goggles, face shields, and gloves. Inspect all glassware for chips and cracks before use, and immediately discard any glassware or plasticware that is damaged. To help protect coworkers in the lab and building care staff, all broken glass should be disposed of in a puncture resistant container labeled as “Broken Glass”. This can be a commercially purchased “broken glass” container or simply a cardboard box or other puncture resistant container labeled as “Broken Glass”.
Whenever cleaning up broken glass or other sharp items, always use a broom, scoop or dustpan, or devices such as pliers, before using your hands to pick up broken pieces. If you have to use your hands, it is best to wear leather gloves when handling broken glass. For other items that can cause cuts or puncture wounds, such as needles and razor blades, never leave these items out in the open where someone could come into contact with them. EHS recommends using a device such as a piece of Styrofoam or similar item to secure them for later use. For disposal, use an appropriate “sharps” container.
If you do receive a cut or injection from a chemically contaminated item, if possible, gently try to remove the object and immediately rinse under water while trying to flush the wound and remove any chemical contamination, administer first aid and seek medical attention if necessary, and then complete an Injury/Illness Report.
7.4.4 Eye and Skin Absorption7.4.4 Eye and Skin Absorption
Some chemicals can be absorbed by the eyes and skin, resulting in a chemical exposure. Most situations of this type of exposure result from a chemical spill or splash to unprotected eyes or skin. Once absorbed by these organs, the chemical can quickly find its way into the bloodstream and cause further damage, in addition to the immediate effects that can occur to the eyes and the skin.
Symptoms of eye exposure can include itchy or burning sensations, blurred vision, discomfort, and blindness. The best way to protect yourself from chemical splashes to the eyes is to always wear safety glasses in the laboratory whenever eye hazards exist (chemicals, glassware, lasers, etc.). If you are pouring chemicals, then splash goggles are more appropriate than safety glasses. Whenever a severe splash hazard may exist, the use of a face shield, in combination with splash goggles is the best choice for protection.
If you do get chemicals in your eyes, immediately go to an eyewash station and flush your eyes for at least 15 minutes. The importance of flushing for at least 15 minutes cannot be overstated! Once the eyewash has been activated, use your fingers to hold your eyelids open and roll your eyeballs in the stream of water so the entire eye can be flushed. After flushing for at least 15 minutes, seek medical attention immediately and complete an Injury/Illness Report.
Symptoms of skin exposure to chemicals include dry, whitened skin, redness, swelling, rashes, blisters, itching, chemical burns, cuts, and defatting.
Laboratory workers can protect their skin from chemical exposure by selecting and wearing the proper gloves, wearing a lab coat and other personal protective equipment for special hazards (such as protective sleeves, face shields, and aprons), and not wearing shorts and sandals in areas where chemicals are being used - even if you are not using chemicals, but someone else in the lab is using chemicals nearby.
For small chemical splashes to the skin, remove any contaminated gloves, lab coats, etc., and wash the affected area with soap and water for at least 15 minutes. Seek medical attention afterward, especially if symptoms persist.
For large chemical splashes to the body, it is important to get to an emergency shower and start flushing for at least 15 minutes. Once under the shower, and after the shower has been activated, it is equally important to remove any contaminated clothing. Failure to remove contaminated clothing can result in the chemical being held against the skin and causing further chemical exposure and damage. After flushing for a minimum of 15 minutes, seek medical attention immediately and complete an Injury/Illness Report.
7.5 Chemical Exposure Limits7.5 Chemical Exposure Limits
The Permissible Exposure Limits (PEL) are based on the average concentration of a chemical to which workers can be exposed to over an 8-hour workday, 5 days per week, for a lifetime without receiving damaging effects. In some cases, chemicals can also have a Ceiling (C) limit, which is the maximum concentration that cannot be exceeded. OSHA has established PELs for over 500 chemicals. Permissible Exposure Limits are legally enforceable.
Another measure of exposure limits are Threshold Limit Values (TLV) which are recommended occupational exposure limits published by the American Conference of Governmental Industrial Hygienists (ACGIH). Similar to PELs, TLVs are the average concentration of a chemical that a worker can be exposed to over an 8-hour workday, 5 days per week, over a lifetime without observing ill effects. TLVs also have Ceiling (C) limits, which are the maximum concentration a worker can be exposed to at any given time. The ACGIH has established TLVs for over 800 chemicals. A main point of difference between PELs and TLVs is that TLVs are advisory guidelines only and are not legally enforceable. Both PELs and TLVs can be found in SDSs. Another good resource for information is the National Institute for Occupational Health and Safety (NIOSH).
7.6 Chemical Exposure Monitoring7.6 Chemical Exposure Monitoring
As a laboratory worker, you may use a variety of potentially hazardous materials on a daily basis. Safe use of these materials depends heavily on following proper laboratory work practices and the utilization of engineering controls. In certain circumstances, it is necessary to verify that work practices and engineering controls are effective in limiting exposures to hazardous materials. EHS Industrial Hygienists can help evaluate the effectiveness of your controls by monitoring exposures to a variety of laboratory materials. Exposure monitoring is the determination of the airborne concentration of a hazardous material in the work environment. Exposure monitoring data is compared to existing OSHA and ACGIH exposure guidelines and is often used to make recommendations concerning engineering controls, work practices, and PPE.
If you think you are receiving a chemical exposure in excess of OSHA exposure limits, such as feeling symptoms commonly associated with exposure to hazardous materials, or work with any of the chemicals listed below, contact EHS at 607-255-8200 and our Industrial Hygienists can use a variety of sampling methods to monitor for any potential exposures.
In some cases, OSHA substance specific standards actually require that the employer conduct initial exposure monitoring.
Examples of chemicals that fall into this category include:
- Vinyl chloride
- Methylene chloride
- Ethylene oxide
Other substances that have exposure monitoring requirements include:
7.7 Toxicity7.7 Toxicity
Toxicity refers to the ability of a chemical to cause harmful effects to the body. As was described by Paracelsus (1493-1541):
There are a number of factors that influence the toxic effects of chemicals on the body. These include, but are not limited to:
- The quantity and concentration of the chemical.
- The length of time and the frequency of the exposure.
- The route of the exposure.
- If mixtures of chemicals are involved.
7.7.1 Toxic Effects7.7.1 Toxic Effects
Toxic effects are generally classified as acute toxicity or chronic toxicity.
- Acute toxicity is generally thought of as a single, short-term exposure where effects appear immediately and are often reversible. An example of acute toxicity relates to the over consumption of alcohol and “hangovers”.
- Chronic toxicity is generally thought of as frequent exposures where effects may be delayed (even for years) and are generally irreversible. Chronic toxicity can also result in acute exposures, with long term chronic effects. An example of chronic toxicity relates to cigarette smoking and lung cancer.
7.7.2 Evaluating Toxicity Data7.7.2 Evaluating Toxicity Data
SDSs and other chemical resources generally refer to the toxicity of a chemical numerically using the term Lethal Dose 50 (LD50). The LD50 describes the amount of chemical ingested or absorbed by the skin in test animals that causes death in 50% of test animals used during a toxicity test study. Another common term is Lethal Concentration 50 (LC50), which describes the amount of chemical inhaled by test animals that causes death in 50% of test animals used during a toxicity test study. The LD50 and LC50 values are then used to infer what dose is required to show a toxic effect on humans.
As a general rule of thumb, the lower the LD50 or LC50 number, the more toxic the chemical. Note there are other factors (concentration of the chemical, frequency of exposure, etc.) that contribute to the toxicity of a chemical, including other hazards the chemical may possess.
While exact toxic effects of a chemical on test animals cannot necessarily be directly correlated with toxic effects on humans, the LD50 and LC50 can give a good indication of the toxicity of a chemical, particularly in comparison to another chemical. For example, when making a decision on what chemical to use in an experiment based on safety for the lab worker, a chemical with a high LD50 or LC50 would be safer to work with, assuming the chemical did not possess multiple hazards and everything else being equal.
In general terms, the resource Prudent Practices in the Laboratory lists the following table for evaluating the relevant toxicity of a chemical:
|Toxicity Class||Animal LD50||Probable Lethal Dose for 70 kg Person (150 lbs.)||Example|
|Super Toxic||Less than 5 mg/kg||A taste (7 drops or less)||Botulinum toxin|
|Extremely Toxic||5 - 50 mg/kg||< 1 teaspoonful||Arsenic trioxide, Strychnine|
|Very Toxic||50 - 500 mg/kg||< 1 ounce||Phenol, Caffeine|
|Moderately Toxic||0.5 - 5 g/kg||< 1 pint||Aspirin, Sodium chloride|
|Slightly Toxic||5 - 15 g/kg||< 1 quart||Ethyl alcohol, Acetone|
In addition to having a toxic effect on the body, some chemicals can be carcinogenic, mutagenic, teratogenic, and acutely toxic. These specific chemical hazards are covered in more detail under the Particularly Hazardous Substances section in this manual.
7.8 Chemical Labeling7.8 Chemical Labeling
The simple rule for chemical labeling is - if a container looks like it contains a chemical (even a clear liquid), then it must be labeled with the contents. Proper labeling of chemicals is one way of informing people who work in laboratories of potential hazards that exist, preventing the generation of unknowns, and facilitating emergency responses such as cleaning up spills and obtaining the proper medical treatment.
New chemical containers have the proper labeling information on the chemical label. The OSHA Laboratory Standard requires that labels on all incoming containers must be maintained and not defaced. As part of laboratory good housekeeping and self-inspections, if any chemical labels appear to be falling off, then laboratory personnel should tape the label back on the container or relabel with a permanent label.
7.8.1 Non-Original Containers7.8.1 Non-Original Containers
Non-original containers (secondary use containers) such as wash bottles, squirt bottles, temporary storage containers, beakers, flasks, bottles, vials, etc. or any container that a chemical from an original container is transferred into, must be properly labeled. In general, EHS recommends writing out the full chemical name and any hazards associated with that chemical. Laboratory personnel are strongly encouraged to use commercially available pre-labeled containers (such as squirt bottles) for chemicals that get used frequently. However, labs can also choose to label chemical containers in other ways such as:
1. Abbreviations - Structures and Formulas
Use of abbreviations such as structures, formulas, or acronyms is acceptable. However, if you use any abbreviations, you must hang up a “key” to the abbreviations in a visible location (preferably close to the chemicals and/or by the door). The “key” must contain the abbreviation and the name of the chemical. Including the hazards of the chemical on the “key” is also useful information. A sample fill-in the blank key can be found on the EHS Signs and Labels webpage. The abbreviation key must be readily available upon request by visitors, emergency responders, and state and federal regulatory agencies such as EPA, OSHA, or New York State Office of Fire Prevention and Control (OFPC) inspectors.
2. Small Containers and Sample Storage:
For small containers, such as vials and eppendorf tubes, which may be too small to write out a chemical name, structure, or formula, laboratories can implement other systems to identify the chemicals such as:
- Placing the vial or small container in a Ziploc bag or other type of overpack container (beaker, plastic bottle, etc.) and labeling the overpack container with the chemical name.
- Laboratories can use “price tag” style labels in which the chemical name is written out on a tag, and the tag is then attached to the small container with string or a rubber band.
- For vials in a test tube rack – laboratory personnel can simply label the rack with the chemical name, and then label the vials with an abbreviation, color, number, or letter code that corresponds to the label on the test tube rack. For example, if a lab had 10 small vials of ethanol in one rack, the rack could be labeled a 1-E = Ethanol. All of the vials would then be labeled as 1-E. Be sure that the number or letter code is clearly identifiable and would not be confused with other chemicals in the lab.
- For preserved specimens, bottles should be labeled with the preservative (i.e. ethanol or formaldehyde). A large number of these labels could easily be produced on the computer using Avery style mailing labels.
- For sample storage in refrigerators, laboratory personnel should label sample containers with one of the above methods, including labeling boxes that hold the small vials or chemical containers. Laboratories should include a key to any abbreviations on the outside of the refrigerator and label the key as “Sample Storage abbreviation = chemical name”.
3. Number, Letter, and Color Codes:
For vials and other small containers, laboratory personnel can make use of number, letter, and color-coded systems as long as a “key” is hung up which clearly identifies the chemical name that the number, letter, or color code represents. While this type of system is available for laboratory personnel to use, EHS does not recommend using such a system for hazardous chemicals. Such a system would be more appropriate for non-hazardous compounds such as agar and buffer solutions.
7.8.2 Labeling Requirements7.8.2 Labeling Requirements
In all cases, regardless of the labeling system used, the following labeling requirements must be followed:
- All chemical containers (both hazardous and non-hazardous) MUST be labeled. Chemical names must be written out in English. If a label is starting to fall off a chemical container or is becoming degraded, then the container needs to be relabeled (using tape, permanent marker, OSHA secondary labels, etc.) or the chemical needs to be transferred to another properly labeled container.
- If abbreviations such as formulas, structures, or acronyms are used, then a “key” to the abbreviations must be hung up in a conspicuous location.
- All personnel working in the laboratory must be fully trained on how to label chemicals using the system and how to understand the labeling system. Training must occur when a new person begins working in the laboratory, when new chemicals are introduced, and should occur on a regular basis or annually.
7.9 Chemical Storage7.9 Chemical Storage
Chemical storage areas in the academic laboratory setting include central stockrooms, storerooms, laboratory work areas, storage cabinets, refrigerators, and freezers. There are established legal requirements as well as recommended practices for proper storage of chemicals. Proper storage of chemicals promotes safer and healthier working conditions, extends the usefulness of chemicals, and can help prevent contamination. Chemicals that are stored improperly can result in:
- Degraded containers that can release hazardous vapors that are detrimental to the health of laboratory personnel.
- Degraded containers that allow chemicals to become contaminated, which can have an adverse effect on experiments.
- Degraded containers that can release vapors, which in turn can affect the integrity of nearby containers.
- Degraded labels that can result in the generation of unknowns.
- Chemicals becoming unstable and/or potentially explosive.
- Citation and/or fines from state and federal regulatory agencies.
7.9.1 General Storage Guidelines7.9.1 General Storage Guidelines
Laboratories should adhere to the following storage guidelines for the proper and safe storage of chemicals. By implementing these guidelines, laboratories can ensure safer storage of chemicals and enhance the general housekeeping and organization of the lab. Proper storage of chemicals also helps utilize limited laboratory space in a more efficient manner.
- All chemical containers MUST be labeled. Labels should include the name of the chemical constituent(s) and any hazards present. Be sure to check chemical containers regularly and replace any labels that are deteriorating or falling off and/or relabel with another label before the chemical becomes an unknown.
- Keep all containers of chemicals closed when not in use.
- Every chemical should have an identifiable storage place and should be returned to that location after use.
- Secondary containment is meant to contain chemicals in the event of a leak or spill. The containment must be big enough to hold 110% of the contents of the primary container.
- The storage of chemicals on bench tops should be kept to a minimum to help prevent clutter and spills, and to allow for adequate working space.
- Chemical storage in fume hoods should be kept to a minimum - limited to the experiment being conducted. Excess storage of chemical containers in hoods can interfere with airflow, reduce working space, and increase the risk of a spill, fire, or explosion.
- For chemical storage cabinets, larger chemical bottles should be stored towards the back and smaller bottles should be stored up front where they are visible. Chemical bottles should be turned with the labels facing out so they can be easily read.
- Chemicals should not be stored on the floor due to the potential for bottles to be knocked over and result in a spill. If it is necessary to store bottles on the floor, then the bottles should be placed in secondary containment, such as trays, and the bottles should be placed away from aisle spaces.
- For multiples of the same chemical, older containers should be stored in front of newer chemicals and containers with the least amount of chemical should be stored in front of full containers. This allows for older chemicals to get used up first and helps to minimize the number of chemical containers in the storage area.
- Do not store chemicals in direct sunlight or next to heat sources.
- Laboratories should strive to keep only the minimum quantity of chemicals necessary. When ordering new chemicals, laboratories should only order enough stock needed for the experiment or the quantity that will get used up within 1 or 2 years at most.
- Liquid chemical containers should be stored in secondary containment, such as trays, to minimize the potential for bottle breakage and minimize the potential for spills.
- Always segregate and store chemicals according to compatibility and hazard classes.
- Chemical containers should be dated when they arrive and should be checked regularly and disposed of when they get past their expiration date. Please Note: Due to the potential explosion hazard, peroxide forming chemicals are required to be tested and dated.
- Flammable liquids in excess of quantities for specific flammability classes must be stored in approved flammable liquid storage cabinets.
- Do not store acids in flammable liquid storage cabinets. This can result in serious degradation of the storage cabinet and the containers inside. Corrosive chemicals should be stored in corrosion resistant cabinets. The exceptions to this rule are organic acids, such as Acetic acid, Lactic acid, and Formic acid, which are considered flammable/combustible and corrosive and can be stored in flammable or corrosive storage cabinets.
- Do not store corrosive or other chemicals that can be injurious to the eyes above eye level. In general and where practical, no chemicals should be stored above eye level.
- Label the outside of refrigerators/freezers to indicate items stored within. For example, "Chemicals only, no food".
- Do not store flammable liquids in standard (non-explosion proof) refrigerators or freezers. Due to the potential explosion hazard, only store flammables in refrigerators or freezers approved by the manufacturer for storage of flammables.
- Highly toxic chemicals such as inorganic cyanides should be stored in locked storage cabinets. Always keep the quantities of highly toxic chemicals to an absolute minimum. See Particularly Hazardous Substances section.
- Be aware of any special antidotes or medical treatment that may be required for some chemicals (such as Hydrofluoric acid).
- Always keep spill kits and other spill control equipment on hand in areas where chemicals are used. Ensure all personnel working in the lab have been properly trained on the location and use of the spill kit.
- For reagent shelves, it is recommended to use shelves with anti-roll lips, to prevent bottles from falling off. This can also be accomplished using heavy gauge twine or wire to create a lip on the shelf.
7.10 Transporting Chemicals7.10 Transporting Chemicals
When transporting chemicals between laboratories or other buildings on campus, the following guidelines should be implemented for protection of people and the environment, and to minimize the potential for spills to occur.
- Whenever transporting chemicals by hand, always use a secondary container such as a rubber acid carrying bucket, plastic bucket, or a 5-gallon pail). If necessary, a small amount of packing material (shipping peanuts, vermiculite, or cardboard inserts), that is compatible with the chemical(s), should be used to prevent bottles from tipping over or breaking during transport. You should have proper PPE accessible in the event of a spill.
- Wheeled carts with lipped surfaces (such as Rubbermaid carts) should be used whenever feasible.
- Whenever possible, do not use passenger elevators when transporting chemicals, only freight elevators should be used. If it is necessary to use a passenger elevator, use should be restricted to low-use times such as early in the morning or late in the afternoon. If this is not possible, be sure to warn passengers, or prohibit passengers from riding with you.
- When transporting compressed gas cylinders, always use a proper gas cylinder hand truck with the cylinder strapped to the cart and keep the cap in place. NEVER roll or drag a compressed gas cylinder.
- Avoid riding in elevators with cryogenic liquids or compressed gas cylinders. If this is necessary, consider using a buddy system to have one person send the properly secured dewars or cylinders on the elevator, while the other person waits at the floor by the elevator doors where the dewars or cylinders will arrive.
- Do not transport chemicals in your personal vehicle. Contact EHS at 607-255-8200 for assistance.
7.11 Chemical Segregation7.11 Chemical Segregation
Chemicals should be stored according to compatibility and hazard classes. Rather than store chemicals alphabetically, or by carbon number, or by physical state, etc., EHS recommends that you segregate them by DOT hazard class first. The potential hazards of storing incompatible chemicals together, and when an emergency occurs, include:
- Generation of heat.
- Possible fires and explosion.
- Generation of toxic and/or flammable gases and vapors.
- Formation of toxic compounds.
- Formation of shock and/or friction sensitive compounds.
- Violent polymerization.
- The benefits of chemical segregation by hazard class include:
- Safer chemical storage.
- Understanding the hazards a chemical exhibits will increase your knowledge about the chemical.
- Identifying potentially explosive chemicals.
- Identifying multiple containers of the same chemical.
There are a number of segregation schemes recommended in the literature by government agencies, chemical manufacturers, safety supply companies, and other universities. However, EHS is recommending segregation of chemicals using a modified version of the Department of Transportation (DOT) Hazard Class System. While this modified DOT system results in most common chemicals being segregated properly, there is no one system that solves all problems. The modified DOT system is less complicated than other segregation schemes and the information to make decisions of which hazard classes to use can easily be found in SDSs, container labels, container markings and stickers, and other resources.
When you are making decisions on how to segregate, keep in mind the following:
- Physical hazards of the chemical.
- Health hazards of the chemical.
- The chemical form (solid, liquid or gas).
- Concentration of the chemical.
Segregation of different chemical hazard classes (such as acids and bases) can occur in the same cabinet as long as there is some form of physical separation, such as using trays with high sides or deep trays. However never store oxidizers and flammables in the same cabinet. Also, do not store compounds such as inorganic cyanides and acids in the same cabinet.
Once chemicals have been segregated, ensure everyone in the lab knows the process and what system is being used. It is best to clearly identify where chemicals in each hazard class will be stored by labeling cabinets with signs, or hazard class labels. These can be purchased from a safety supply company, you can create your own, or download FREE labels from the EHS Signs and Labels webpage.
If you need assistance with cleaning out your lab of old and excess chemicals, or would like assistance with segregating your chemicals, contact EHS at askEHS@cornell.edu. EHS also offers an online training class on Chemical Segregation. Examples of incompatible chemicals can be found in the appendix.
7.11.1 EHS Modified DOT Hazard Class System7.11.1 EHS Modified DOT Hazard Class System
The basic DOT hazard classes and hazard class numbers are:
|DOT Hazard Class Number||Hazard Class|
|Class 2||Compressed gases|
|Class 3||Flammable liquids|
|Class 4||Flammable solids|
|Class 7||Radioactive materials|
|Class 9||Store with Class 6|
The DOT hazard class numbers can be found on hazard class labels, in SDSs (under the “Transportation Information Section”), on container labels, and in other reference texts. An explanation of the DOT Hazard Class system can be found in the DOT Training Modules and an expanded version of the DOT hazard classes can be found on the EHS Signs and Labels webpage.
The EHS chemical segregation scheme modifies the DOT system by breaking down hazard classes into subcategories. A handout on the EHS Chemical Segregation Scheme can be found in the appendix.