CHAPTER 3: CHEMICAL CLASSIFICATIONS AND USE GUIDELINES

Corrosive Liquids Personal Protective Equipment (PPE)

When working with corrosives (i.e. acids, based, amines, etc.) follow these requirements:

*A fume hood sash, when properly lowered and used, can be substituted for a face shield.

Flammable chemicals are classified as having a flash point of less than 100 °F. An understanding of the following terms is helpful when working with flammable chemicals:

• Flash point--the lowest temperature at which the vapor above the liquid will ignite if an ignition source is present. The flash point for ethyl ether is - 49 °F.

• Ignition/Autoignition temperature--the minimum temperature required to initiate or cause self-sustained combustion which is independent of a spark or flame source.

• Limits of flammability--each flammable gas and liquid (in the form of a vapor) has two limits which define the range of concentrations in mixtures with air that will propagate flame and explode.

•• LFL or Lower flammable limit--the percent by volume

concentration below which the mixture is too lean to burn.

•• UFL or Upper flammable limit--the percent by volume

concentration below which the mixture is too rich to burn.

•• The flammable range consists of all the concentrations between these two limits.

• Spontaneous combustion or ignition--this phenomenon takes place when, without the application of an external heat source, a substance reaches its ignition temperature.

• When working with flammable chemicals:
• Keep in covered containers when not actually in use.
• Keep all sources of ignition, high heat and combustion remote from storage and dispensing areas. Always keep most organic solvents away from inadvertent contact with oxidizers.
• Dispense all solvents within a fume hood.
• Do not use Nalgene carboys for storage of flammable liquids. Follow the flammable liquid container size limits found in Appendix 11.
• Do not store flammable liquids on the floor.
• Store and use in the smallest amounts possible so that any spill can be cleaned up before it can cause a large fire.

Chemical Lists # 3, 4, 17 & 18 list common flammable chemicals.

Static Electricity, Bonding and Grounding

Static electricity is generated by the contact and separation of dissimilar materials. For example, static electricity is generated when a fluid flows from a container opening down a funnel, through agitation and mixing and through filling a container which causes splashing. In the case of flammable liquids, spark discharges from the static electricity build-up may have enough energy to ignite the flammable vapors present. In order to prevent these discharges by providing a good electrical-conductive path, proper bonding and grounding procedures of the equipment involved must be carried out.

By definition, bonding is a procedure which eliminates static-electrical-charge differences between two or more objects. Grounding, on the other hand, is a procedure which eliminates a potential difference between an object and the ground (earth).

When two objects are bonded, the charges flow freely between the objects and there is no difference in their charge. Bonding will not eliminate the static charge but will equalize the potential between the objects bonded so that a spark will not occur between them. Bonding will eliminate a difference in potential between objects that are bonded. However, it will not eliminate a difference in potential between these objects and the earth, unless one of the objects has an adequate conductive path to earth. An adequate ground, which will continuously discharge a charged conductive body, is necessary to complete the conductive path.

Bonding and grounding are only effective when the bonded objects are made of conductive materials. Plastics can accumulate significant static electrical charge without

allowing the charge to disperse enough through the material. Therefore, non-approved

plastic containers and funnels should not be used when transferring flammable liquids in quantities larger than one gallon.

The equipment necessary to carry out bonding and grounding is available in the stockroom.

Bonding and Grounding Procedures for transferring flammable liquids in quantities greater than one gallon:

Please note that only metal funnels and the appropriate containers, preferably plastic safety cans, should be used. Please see Appendix 11 for flammable liquids container

requirements. Whenever possible, perform the transfer in a fume hood.

1.  Using a bonding/grounding wire, connect the original container to the funnel. Using another wire, connect the funnel to the receiving container. If the containers involved are metal and coated in some way (paint, plastic), scrape down to the metal with the clamp on the wire to ensure a good connection.

2. Using a bonding/grounding wire, connect the container to a ground source such as the water spigot in the hood or another conductive metal source. Ensure good connections.

3. Perform the transfer.

Academic Use

Proper laboratory procedures to follow when working with infectious or potentially infectious agents are not within the scope of this CHP. Prudent practices to follow when working with these agents are contained in reference texts such as the Centers for Disease Control and National Institute of Health’s "Biosafety in Microbiological and Biomedical Laboratories"--NIH No. 88-8395 and the National Research Council’s "Biosafety in the Laboratory" available through the Environmental Health and Safety Officer’s reference library.

Additionally, the CSB and SJU bloodborne pathogens written policy, as required by 29 CFR 1910.1030, are available through the safety offices of each campus. Under these policies laboratory work involving human blood or other potentially infectious materials must be reviewed by the Environmental Health and Safety Officer before any work commences.

Potential Exposure Incidents

All faculty, staff, student employees and students must take steps to lessen the chance of exposure to human blood and other potentially infectious materials. Gloves must beworn whenever the potential for contact with an open wound exists. Bloodborne Pathogen Supply kits, which contain gloves and all of the supplies necessary to clean-up areas contaminated by potentially infectious materials, are available in the stockroom and rooms 213, 237 and 238.

Please see Chapter 4 for more information on emergency response. Additionally, theCSB and SJU bloodborne pathogens policies contain more information on related issues.

Unstable or reactive chemicals are those which in the pure state or as commercially produced, will vigorously polymerize, decompose, condense or will become self-reactive under conditions of shock, pressure or temperature. Compounds containing the following functional groups tend to be sensitive to heat and shock: acetylide, diazo, nitroso, peroxide, azide, halamine, ozonide.

Compounds containing nitro groups may be highly reactive, especially if other substituents such as halogens are present. Treat the following groups with respect, especially at higher temperatures: perchlorates, nitrates, chlorites, chlorates, bromates, iodates. Highly reactive chemicals may be included on the list of chemicals requiring prior approval. Please consult those guidelines before use. (Section 2.7 and Appendix 4)

Special handling procedures for highly reactive chemicals:

Consult guidelines in the appropriate references or MSDSs before using chemicals exhibiting these properties.

• Research advisors are responsible for informing their research students of the hazards associated with working with highly reactive chemicals before any work commences.
• Bring these chemicals into the laboratory only as required and then in the smallest possible quantities.
• Do not mix even small quantities with other chemicals without prior knowledge of the hazards involved.
• Wear safety goggles, a lab coat, appropriate gloves and use an explosion shield.
• Highly reactive chemicals cannot be stored in the same room as flammable liquids. Please see the stockroom manager for the designated storage location.

Lists of common reactive and explosive chemicals are included as Chemical List # 10, 11, 14, 15 & 16. Additionally, lists of common oxidizers and oxidizer chemical families are included as Chemical Lists # 6 & 7.

Radioactive materials will not be used in Ardolf Science Center.

Toxicity

Parameters for judging the toxicity of a chemical include the following terms:

• Permissible Exposure Limits (PELs) are OSHA-regulated values which define the legal air contaminant concentrations in the workplace. PELs are expressed in ppm (parts of vapor or gas per million parts of air by volume at room temperature and atmospheric pressure) or mg/m3 (milligrams of particulate per cubic meter of air).

• Threshold Limit Values (TLVs) refer to airborne concentrations of substances and represent conditions under which it is believed that nearly all workers may be repeatedly exposed day after day without adverse health effects. TLVs can be further broken down into:

Time-Weighted Average (TLV-TWA) is the time-weighted average concentration for a normal 8-hour workday and a 40-hour workweek.

Short-Term Exposure Limit (TLV-STEL) is the concentration to which persons can be exposed for a period of up to 15 minutes continuously without suffering irritation, chronic or irreversibly tissue change or narcoses.

TLV have been determined by the American Conference of Governmental Industrial Hygienists, ACGIH.

In general the lower the LD50, PEL or TLV, the more hazardous the material.

Chemical List # 23 is the University of Minnesota list of regulated chemicals, with their PELs and TLVs. The U of M list also includes notations of MREP (male reproductive toxin), FREP (female reproductive toxin) and DTOX (developmental toxin). Additionally, the following common lists, compiled from 33 State and Federal Regulatory Lists, are found in the Chemical List section :

Chemical List # Chemical Group

1 & 12 Carcinogens

19 Extreme Acute Health Ratings

20 Extreme Chronic Health Ratings

21 Neurotoxins

1 & 22 Teratogens

Carcinogens

According to Hawley’s Condensed Chemical Dictionary, 11th Edition, there are approximately 3500 known and suspected carcinogenic compounds, with new compounds being discovered continually. The following groups publish lists of carcinogenic substances:

• National Toxicology Program as "known to be carcinogenic" or "reasonably anticipated to be carcinogens" in the latest edition of the Annual Report on Carcinogens.
• Occupational Safety and Health Administration (OSHA) regulated as such in 29 CFR 1910.1000, Subpart Z.
• International Agency for Research on Cancer (IARC) as Group 2A or 2B in the latest edition of Monographs.

Please see the University of Minnesota list of regulated chemicals, Chemical List # 23, columns P, Q and R for more specific information.

Safety Guidelines:

A minimum set of guidelines that should be followed when working with reproductive toxins, carcinogens, acutely toxic chemicals and experimental chemicals with unknown toxicity are listed below. The Lab Coordinator or Research Advisor should ensure that these and other necessary precautions are taken when working with these substances.

• Use of these chemicals must be approved by the Lab Coordinator or Research Advisor before beginning any reaction, manipulation or operation. Please note that some of these chemicals may also require prior approval or notification before use. See Appendix 4 for guidelines.
• All work must be performed in a functioning fume hood, biological safety cabinet, ventilated glove box, sealed system or other system designed to minimize exposure to these substances.
• Gloves and other appropriate protective apparel must be worn when working with these chemicals. Check the chemical’s MSDS for the appropriate personal protective equipment.
• The quantities used and stored in the laboratory and their concentrations in solution or mixtures must be minimized.
• Decontaminate and clean the work area at appropriate intervals. Follow a procedure approved by the Lab Coordinator in consultation with the Environmental Health and Safety Officer. The interval may be as short as one day or as long as six months depending upon the frequency of usage and level of hazard.
• All contaminated wastes must be collected and disposed of in a timely and appropriate manner as outlined in the CSB/SJU CHP. For more specific disposal information contact the Environmental Health and Safety Officer.
• When not in use, these chemicals should be stored in a limited access area and within protective containment devices.
• Volatile substances should be kept cool and contained.
• Dispersible solids should be kept in closed containers, used in places with minimum air currents, and suitable contact materials should be used to avoid static charge buildup.
• Compressed gas cylinders which contain acutely toxic chemicals such as arsine and nitrogen dioxide must be kept in ventilated gas cabinets.
• Ensure control of gases by using piping, valves and containers which can withstand pressure buildup.
• Detection equipment may be required in laboratories where chemicals (especially poisonous gases) with a high degree of acute toxicity are utilized.
• Anyone whose work involves regular and frequent handling of toxicologically significant quantities of a chemical should consult with the Environmental Health and Safety Officer to arrange for a qualified physician to determine whether a regular schedule of medical surveillance is desirable.
• Employees must comply with the recommendations contained in the National Institutes of Health (NIH) publication entitled "NIH Guidelines for the Laboratory Use of Chemical Carcinogens," which is available through the Environmental Health and Safety Officer’s safety reference library.