4.1  High Risk Hazardous Chemicals

4.1.1  High Risk Hazardous Chemical Definition

4.1.2  Approval for Use of High Risk Hazardous Chemicals

4.1.3  Work Procedures for High Risk Hazardous Chemicals

4.1.4  Recordkeeping Requirements for High Risk Hazardous Chemicals

4.1.5  Posting Requirements for High Risk Hazardous Chemicals

4.1.6  Training Requirements for High Risk Hazardous Chemicals

4.2  Moderate Risk Hazardous Chemicals

4.3  Physical Hazards

4.3.1  Flammable & Combustible Liquids  Definition/General Information  Special Precautions - Working with Flammables & Combustibles

4.3.2  Peroxides  Definition/General Information  Special Precautions - Working with Peroxides

4.3.3  Oxidizers  Definition/General Information  Special Precautions - Working with Oxidizers

4.3.4  Pyrophorics  Definition/General Information  Special Precautions - Working with Pyrophorics

4.4  Health Hazards

4.4.1  Corrosives & Irritants  Definition/General Information  Special Precautions - Working with Corrosives & Irritants

4.4.2  Sensitizers  Definition/General Information  Special Precautions - Working with Sensitizers

4.4.3  Toxic Chemicals  Definition/General Information  Special Precautions - Working with Toxic Chemicals

4.4.4  Reproductive Hazards  Definition/General Information  Special Precautions - Working with Reproductive Toxins

4.4.5  Carcinogens  Definition/General Information  Special Precautions - Working with Carcinogens  Asbestos

4.5  Department of Homeland Security "Chemicals of Interest"

4.1       High Risk Hazardous Chemicals

High Risk Hazardous Chemicals are those that require stringent controls for their containment because they are extremely hazardous to laboratory personnel, could cause toxic effects or disease if released to the environment, or are regulated as a Select Agent.  Due to a combination of hazardous properties (e.g., vapor pressure, toxicity) these chemicals must be considered to be an extreme health hazard when used under any conditions.  In general, an accidental exposure to one of these chemicals may result in cancer, serious illness or death. 

4.1.1       High Risk Hazardous Chemical Definition

A chemical shall be considered for classification as a high risk hazardous chemical if at least one of the following criteria is met:

·         the substance is acutely toxic (causing death or bodily harm) with an LD-50 of 100 mg/kg or less by any route of exposure

· the substance is chronically toxic (includes tumor incidence, birth defects, or other serious health effects) at levels below:

a.  5.0 mg/kg per day oral exposure

b.  30 mg/kg per week dermal exposure

c.  5.0 mg/m3 by inhalation exposure based on long term studies and chronic exposures

· the substance is listed as a Select Agent toxin 

A list of chemicals currently classified as high risk hazardous chemicals is in Appendix A of this chapter.

4.1.2       Approval for Use of High Risk Hazardous Chemicals

Principal Investigators are required to submit a detailed “Safety Plan for the Use and Storage of High Risk Hazardous Chemicals to the Chemical Safety Committee prior to obtaining, storing, or using the high risk hazardous chemical.  This plan will be updated annually.  EHS B&C will assist the Principal Investigator in the preparation of this written plan.  The “Safety Plan for the Use and Storage of High Risk Hazardous Chemicals” form and instructions are in Appendix B.

4.1.3       Work Procedures for High Risk Hazardous Chemicals

All work with high risk hazardous chemicals will be performed according to the procedures established in the approved Safety Plan.  The Safety Plan specifies facilities, equipment, work practices (including use of engineering controls such as chemical fume hoods and required PPE), decontamination, storage, shipping/transfers and disposal for the high risk hazardous chemical.

4.1.4       Recordkeeping Requirements for High Risk Hazardous Chemicals

The Principal Investigator is required to keep an Inventory Control log book for the chemical.  This book will contain the name of the agent, the name of the Principal Investigator, date of receipt, how and where the agent is used and stored, and the method and date of disposal.  All of the agent must be accounted for in the record.  This log book will be reviewed by EHS B&C during the annual Lab Audit.

4.1.5       Posting Requirements for High Risk Hazardous Chemicals

All doors to the work area where these chemicals are used or stored shall be posted with a sign stating “Caution Hazardous Chemicals Authorized Personnel Only”.  The sign will be yellow with black lettering and at least four by six inches in size.  These signs are available from EHS B&C.

4.1.6      Training Requirements for High Risk Hazardous Chemicals

All personnel working with a high risk hazardous chemical must be included in the Safety Plan and approved by the Chemical Safety Committee.  These employees must be trained in the hazards of the chemical, the approved Safety Plan and any other special procedures required for working with the chemical.  All training must be documented and provided for review by EHS B&C or the Chemical Safety Committee upon request.


4.2       Moderate Risk Hazardous Chemicals

Moderate risk hazardous chemicals present a moderate to severe health hazard if not handled properly.  They include confirmed or suspected carcinogens, reproductive toxins, chronic toxins and acute poisons that do not fall into the high risk category.  Moderate risk hazardous chemicals should be handled as “particularly hazardous substances” as described in section 3.2.4.


4.3       Physical Hazards

4.3.1      Flammable & Combustible Liquids      Definition/General Information

The degree of flammability of a chemical is determined by the temperature at which the chemical gives off enough vapors to form an ignitable mixture with air to support combustion in the presence of an ignition source.  This is known as the chemical’s Flash Point.  Flammable liquids have flash points below 100o F and vapor pressure at or below 40 pounds per square inch at 100o F.  Combustibles have flash points at or above 100o F and below 200o F.  A chemical’s flash point can be found in the MSDS in the Fire Fighting section.      Special Precautions - Working with Flammable & Combustible Liquids

Many flammable and combustible liquids are solvents with high vapor pressures.  Working with them creates an inhalation exposure hazard.  To minimize exposure potential, it is recommended that work be done inside a chemical fume hood.  Solvents also tend to defat the skin causing dermatitis.  Some can be absorbed through the skin, another exposure source.  For this reason, it is important to select and use gloves appropriate for the chemical. 

Ignition sources should be eliminated in the work area when working with flammables and combustibles.  Flammable vapors can travel a considerable distance and ignite when an ignition source is found.  For this reason, control of vapor accumulation by working in a chemical fume hood is good practice.  Fire extinguishers appropriate for the materials being used should be available. 

Store flammable liquids in National Fire Protection Association (NFPA) approved safety cabinets or safety cans.  Label each safety cabinet with the maximum gallon capacity rated or allowed.  The cabinet below the laboratory hood is considered suitable for storage if it is vented and labeled for flammable storage.  Containers should be kept tightly closed at all times when not in use.  Refrigeration equipment for storage of flammables must be rated for flammable storage (i.e., must not have any exposed ignition sources such as lights or switches inside the unit).  Equipment used in the transfer of flammable materials must be grounded.  During transfer containers must be bonded as well.

4.3.2      Peroxides      Definition/General Information

Organic peroxides are compounds with a bivalent O-O structure.  Organic peroxides can be present intentionally as initiators for free radical reactions or unintentionally as contaminants in peroxide-forming chemicals.  The latter case usually occurs when theses chemicals are exposed to air after opening.  Peroxides, especially in the dry crystalline state, are unstable, shock-sensitive and can detonate upon contact with heat, friction, impact, light and other chemicals such as strong oxidizers or reducing agents.  Some chemicals known to form peroxides have stabilizers or free-radical scavengers to inhibit peroxide formation.  Some examples of common peroxide formers are ethers and aldehydes. 

In contrast, inorganic peroxides are not combustible, but react vigorously with water to release oxygen.  Reaction with organic and oxidizable substances may cause fire.      Special Precautions - Working with Peroxides


Inherent to the safe use of these chemicals is the dating of all chemicals as soon as received and again when opened.  Testing and disposal procedures for peroxides should be based on the opening date according to the following table.  These procedures should be part of the laboratory’s Chemical Hygiene Plan.

Class I:  Unsaturated materials, may polymerize violently and hazardously

Class II:  Hazard upon concentration

Class III:  Peroxides derived may explode without concentration



vinyl acetylene

vinyl acetate

vinyl chloride



ethyl ether







isopropyl ether

divinyl acetylene

vinylidene chloride


sodium amide

Discard at 12 Months

Discard at 12 Months

Discard at 3 Months

*  When stored as a liquid, the peroxide-forming potential increases and the chemical should then be considered a Class III. 

Store at the lowest possible temperature consistent with solubility and freezing point. DO NOT STORE  LIQUID PEROXIDES/SOLUTIONS BELOW FREEZING PRECIPITATION POINTS.  Store in a cool, dark, well-ventilated area. 

For those materials with a high potential for peroxide formation, consider storage in inert atmospheres (nitrogen or argon) or under vacuum.  Also, explore the possibility of purchasing the chemical under nitrogen in septum-capped bottles.  Glass containers that have screw-cap lids or glass stoppers should not be used due to the potential for friction or grinding.  Polyethylene bottles with screw tops may be used.  Never return unused chemical to the original container due to the potential for contamination. 

Peroxide Testing

Chemicals known to form peroxides should be tested for peroxides periodically (every 3 to 6 months is recommended, depending on the Class (see table above).

· Peroxide test strips are available commercially.  A color change occurs in the presence of peroxides.

· Test using acetic acid and potassium iodide:  Add one to three milliliters of the test liquid to an equal volume of acetic acid, add a few drops of 5% potassium iodide solution, and mix gently.  A yellow to brown color indicates the presence of peroxides.

· Test using potassium iodide:  Add one milliliter of freshly prepared 10% potassium iodide solution to ten milliliters of the organic test liquid in a 25-milliliter glass cylinder.  A yellow color will indicate the presence of peroxides.

If a chemical tests positive for peroxides, contact EHS EPM for proper handling and disposal.

4.3.3      Oxidizers      Definition/General Information

An oxidizer is a substance that gives up oxygen easily to stimulate combustion of other materials.  Oxidizers can react violently when they come in contact with reducing agents, metals and sometimes ordinary combustibles.  This group includes peroxides, permanganates, nitrates and chromates.  Some common oxidizers include perchloric acid and the chromic acid solution used to clean glassware.  Besides the fire hazard, many oxidizers are corrosive as well.      Special Precautions - Working with Oxidizers


Store oxidizers in inert, unbreakable containers.  Do not use rubber or cork stoppers as they are potentially oxidizable substances.  Store away from reducing agents, flammables and combustible materials.


Use of lab apparatus should be reviewed carefully to ensure contaminants are not inadvertently added.  For example, magnetic stirring bars can add metal traces to a solution causing violent unexpected reactions.

4.3.4      Pyrophorics      Definition/General Information

Pyrophorics are materials that can spontaneously combust upon exposure to air without the addition of external heat.  Ignition may be delayed or instantaneous depending on the material.  Some common pyrophorics include alkyl lithiums, alkali metals (sodium, potassium), trialkylaluminum reagents, alkylboranes, finely divided metals (calcium, zirconium), metal powders (magnesium, zinc) and metal/nonmetal hydrides.      Special Precautions - Working with Pyrophorics

Pyrophorics should be stored under an atmosphere of inert gas or as otherwise recommended by the manufacturer.  Pyrophorics should be isolated from oxidizing materials, ignition sources, heat and flammable or combustible materials.


4.4       Health Hazards

4.4.1      Corrosives & Irritants      Definition/General Information

Corrosives are substances that cause visible destruction or irreversible alterations in human tissue at the site of contact.  Corrosive chemicals typically have a pH >12 or < 2.  Common corrosives are acids and bases. 

Irritants are substances that cause a reversible inflammatory effect on living tissue by chemical action at the site of contact.  Irritants typically have a pH between 2 and 12.  A common irritant used at UTMB is formalin.      Special Precautions - Working with Corrosives & Irritants

Precautions when working with corrosives and irritants are primarily to prevent exposure via inhalation, ingestion and skin contact, to the extent possible.  This includes working inside of a chemical fume hood, practicing good hygiene (e.g., hand washing) and wearing appropriate PPE for the chemical(s) in use.

4.4.2      Sensitizers      Definition/General Information

A substance that may cause no reaction in a person during initial exposures, but upon further exposures will cause an allergic response to the substance.  Sensitization may be caused via respiratory and/or skin exposure, depending on the chemical.  Prevalence of sensitization varies in a population repeatedly exposed to a given chemical sensitizer.  Some individuals are more likely to become sensitized than others.  Common sensitizers include formaldehyde, hydroquinone, chromic acid, acrylates and isocyanates.      Special Precautions - Working with Sensitizers

Precautions when working with sensitizers are primarily to prevent exposure via inhalation, ingestion and skin contact, to the extent possible.  This includes working inside of a chemical fume hood, practicing good hygiene (e.g., hand washing) and wearing appropriate PPE for the chemical(s) in use.  If sensitization is suspected, the employee should report to Employee Health for medical evaluation since severe cases may require removal from areas using the chemical in question.

4.4.3      Toxic Chemicals      Definition/General Information

Toxic chemicals are substances that can cause severe illness, poisoning, disease, or death when ingested, inhaled, or absorbed by living organisms.  The most common work-related exposure routes for toxic chemicals are inhalation, ingestion and skin absorption (for chemicals that can be absorbed through the skin).  Toxic chemicals may have systemic effects or target particular organs of the body.  Some common toxic chemicals include benzene, formaldehyde and ethylene oxide.      Special Precautions - Working with Toxic Chemicals

Precautions when working with toxic chemicals are primarily to prevent exposure via inhalation, ingestion and skin contact, to the extent possible.  This includes working inside of a chemical fume hood, practicing good hygiene (e.g., hand washing) and wearing appropriate PPE for the chemical(s) in use.  For moderate and high risk hazardous chemicals, see sections 4.2 and 4.1, respectively, for additional information.

4.4.4      Reproductive Hazards      Definition/General Information

Reproductive toxins affect male and/or female reproductive capabilities, cause chromosomal damage (mutagens) and/or affect the fetus (teratogens).  Some examples of reproductive toxins are provided in the following table.




Reduced birth weight, spontaneous abortions

Ethylene oxide

Malformed fetuses, miscarriages, decreased sperm count

Nitrous oxide

Low birth weight, impaired development, spontaneous abortion, decreased fertility

Antineoplastic drugs

Malformations, fetal loss, sterility


Congenital malformations, fetal alcohol syndrome, reduced birth weight, increased stillbirth rate


Chromosomal aberrations, genetic mutations, fetal death


Skeletal and CNS abnormalities

Anesthetic gases

Spontaneous abortion, decreased birth weight, stillbirth, increased frequency of cardiovascular birth defects

Carbon disulfide

Premature births


Decreased birth weight, premature labor, stillbirths      Special Precautions - Working with Reproductive Toxins

Precautions when working with reproductive toxins are primarily to prevent exposure via inhalation, ingestion and skin contact, to the extent possible.  This includes working inside of a chemical fume hood, practicing good hygiene (e.g., hand washing) and wearing appropriate PPE for the chemical(s) in use.  These chemicals generally fall into the moderate risk category.  See section 4.2 for additional information.

4.4.5      Carcinogens      Definition/General Information

A carcinogen is a substance that may cause cancer in animals or humans.  Some examples of known human carcinogens are aflatoxins, asbestos, arsenic, benzene, ethylene oxide, Hepatitis B virus, Hepatitis C virus, mustard gas and 2-naphthylamine.      Special Precautions - Working with Carcinogens

Precautions when working with carcinogens are primarily to prevent exposure via inhalation, ingestion and skin contact, to the extent possible.  This includes working inside of a chemical fume hood, practicing good hygiene (e.g., hand washing) and wearing appropriate PPE for the chemical(s) in use.  These chemicals generally fall into the moderate risk category.  See section 4.2 for additional information.      Asbestos

The UTMB Asbestos Operations and Maintenance Program provides a consistent approach to maintenance and repair activities which might disturb asbestos as required by the Texas Administrative Code.  It also provides guidance for asbestos issues in renovation/construction projects as part of a comprehensive plan for the control of asbestos hazards on the UTMB campus.

The procedures detailed in the program manual cover repair, maintenance and renovation activities at UTMB owned or maintained facilities.  The scope includes small scale, short duration operation and maintenance projects as well as larger scale abatement projects for renovation.  Procedures applicable to housekeeping/custodial and vehicle maintenance activities are also included.


4.5       Department of Homeland Security "Chemicals of Interest"

The U.S. Dept. of Homeland Security (DHS) issued a Federal regulation 6 CFR Part 27 "Chemical Facility Anti-Terrorism Standards" in 2007.  UTMB is subject to this regulation.  Integral to this regulation is a list of "Chemicals of Interest" with threshold quantities. Within sixty days of acquiring any “Chemicals of Interest” above the threshold quantities, we must file a report with the Dept. of Homeland Security.   

Since quantities are cumulative campus-wide, although a particular PI may be purchasing a quantity below the threshold, the total possession quantity of the chemical for the entire campus must be evaluated to determine if a threshold will be exceeded.  This is similar to our UTMB Radioactive Material Use License which also has UTMB campus limits per radionuclide.  Because of this, prior to acquiring any quantity of a “Chemical of Interest”, EHS must be contacted to determine if the acquisition will trigger a reporting requirement.  If we are required to report possession of a Chemical of Interest above a threshold, this report will trigger a risk assessment by Dept. of Homeland Security.  Based on their risk assessment, we may be required to take further security measures.  Failure to comply with this regulation could result in penalties up to $25,000 for each day of non-compliance.  Due to these requirements, acquisition of these chemicals must be limited to the extent possible.  Appendix C contains the list of DHS “Chemicals of Interest”.