Handling Chemicals of Low to Moderate Toxicity

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Overview
Chemicals of low to moderate toxicity are commonly used in laboratories. Low toxicity is defined as chemicals having an LD50 orally in rats value of >5g/Kg. Moderate toxicity is defined as chemicals having an LD50 orally in rats value of 0.5-5g/Kg. This information can be found on a chemical’s Material Safety Data Sheet (MSDS) or by contacting Environmental Health and Safety (EHS). This Update provides basic guidelines for using these chemicals in laboratories. It is to be used as a general Standard Operating Procedure (SOP) in addition to the College’s Chemical Hygiene Plan. More specific SOP’s may need to be developed depending upon the hazard.

Applicability
This Update applies to all College laboratory students, faculty, staff, and visitors working with chemicals of low to moderate toxicity.

Responsibilities
Laboratory Workers will read this update, follow the procedures outlined and contact their supervisor or EHS for additional assistance.

Principal Investigators and Laboratory Supervisors will ensure all laboratory personnel are aware of this update and adhere to the requirements. They will provide training and contact EHS for additional assistance as needed.

Environmental Health and Safety (EHS) will assist all students, faculty, staff and visitors in implementing this Update and monitor the College for compliance with the procedures.

Procedure
General Rules: The following should be used for general laboratory work with chemicals:

  • Accidents and Spills – Eye Contact: Promptly flush eyes with water for a prolonged period (15 minutes) and seek medical attention. Report incident to your supervisor or Principal Investigator.
  • Skin Contact: Promptly flush the affected area with water and remove any contaminated clothing. If symptoms develop or persist after washing, seek immediate medical attention.
  • Clean up: Follow the guidelines in the EHS Update “Chemical Spill Planning and Response”.

Avoidance of “Routine” Exposure: Develop and encourage safe habits. Avoid unnecessary exposure to chemicals by any route. Do not smell or taste chemicals. Vent apparatus that may discharge toxic chemicals (vacuum pumps, distillation columns, etc.) into local exhaust devices, such as chemical hoods. Test glove boxes and inspect gloves for proper function before use. Do not allow release of toxic substances in cold rooms and warm rooms, since these have contained recirculated atmospheres, with no dilution of vapors or gases.

Choice of Chemicals: Use only those chemicals for which the quality of the available ventilation system is appropriate. Chemical hoods must be used, if the chemicals are noxious or have toxic properties.

Use of Chemical Hood: Use the hood for all operations which might result in release of toxic chemical gases, vapors or dust. As a general rule, use a hood or other local ventilation device when working with any appreciably volatile substance with a Permissible Exposure Limit (PEL) or Threshold Limit Value (TLV) of less than 50 ppm. Consult the MSDS for TLV or PEL. Confirm adequate hood performance before use. Do not use a hood with flow less than 100 linear feet per minute. Keep hood closed at all times except when adjustments within the hood are being made. Keep materials stored in hoods to a minimum and do not allow them to block vents or air flow. Contact EHS to verify chemical hood performance.

Food and Drink: No eating, drinking, or gum chewing is permitted in areas where laboratory chemicals are present. Wash hands before conducting any of these activities. Avoid storage, handling or consumption of food or beverages in storage areas and refrigerators, or when glassware or utensils are used for laboratory operations.

Equipment and Glassware: Handle and store laboratory glassware with care to avoid damage. Do not use damaged glassware. Use extra care with Dewar Flasks and other evacuated glass apparatus. Shield or wrap them to contain chemicals and fragments should implosion occur. Use equipment only for its designed purpose.

Exiting: Wash areas of exposed skin before leaving the laboratory. Remove laboratory coats before leaving the laboratory.

Horseplay: Avoid practical jokes or other behavior which might confuse, startle or distract another worker.

Mouth Suction: Do not use mouth suction for pipetting or starting a siphon. Use a squeeze bulb, house vacuum or Bernoulli device for these functions.

Personal Apparel: Application of cosmetics and lotions is prohibited in labs with chemicals. Confine long hair and loose clothing. Wear shoes at all times in the laboratory. Do not wear sandals, open toe or perforated shoes or sneakers, when handling hazardous materials.

Personal Housekeeping: Keep your work area clean and uncluttered, with chemicals and equipment properly labeled and stored. Clean up the work area on completion of an operation or at the end of each day.

Personal Protection: Use protective and emergency apparel and equipment as appropriate. Assure that appropriate eye protection is worn by all persons, including visitors, where chemicals are stored or handled. Use face shields in addition to eye protection for work with strong corrosives. Know the location of emergency showers and eye wash stations and maintain free access to these devices. Wear appropriate gloves when the potential for contact with toxic materials exists. Inspect the gloves before each use, wash them before removal, and replace them when damaged, signs of degradation appear, or periodically with continued use. Remove laboratory coats immediately on significant contamination. Launder or discard disposable coats periodically.

Use appropriate respiratory equipment when air contaminant concentrations are not sufficiently restricted by engineering controls. Consult Environmental Health and Safety on selection of respirators and their use before ordering or using such devices. A medical evaluation and fit-test are required before using a respirator.

Planning: Seek information and advice about hazards, plan appropriate protective procedures, and plan positioning of equipment before beginning any new operation. Obtain Material Safety Data Sheets (MSDS’s) and collect them in a central location within your laboratory. Develop a procedure covering use, storage and disposal of chemicals associated with the procedure.

Unattended Operation: In the event of failure of a utility service (such as cooling water) to an unattended operation, leave lights on, place an appropriate sign on the door, with a hazard warning and the danger associated, and provide for containment of toxic substances. If at all possible, avoid this practice.

Vigilance: Be alert to unsafe conditions and see that they are corrected when detected. Watch for overcrowding or overstorage of hazardous chemicals. Do not store incompatibles together. Do not store corrosives and poisons above waist height.

Waste Disposal: All laboratory operations must include plans and training for waste disposal. Contact Environmental Health and Safety for advice on chemical waste disposal before conducting an experiment. Deposit chemical waste in appropriate receptacles labeled with the WMC hazardous waste label and follow all other waste disposal procedures of the Weill Medical College “Chemical Hygiene Plan” and “Waste Disposal Procedures” booklets. Only approved chemicals may be sewered or placed in the trash. Chemical Collection Requests may be made online at the Environmental Health and Safety website.

Working Alone: Avoid working alone on a project. Do not work alone in a laboratory if the procedures being conducted are hazardous. Do not work late nights or weekends with toxic or hazardous chemicals, unless the procedure is a standard practice and poses no exceptional risks to personnel.

Prior to initiation of experiments, all employees must consult the Material Safety Data Sheets (MSDS) for all reagents to be used in the protocol. Employees will familiarize themselves with hazards and will use the information contained on the MSDS to select the correct personal protective equipment (gloves, disposable suits, etc.), protective devices and safe storage and disposal practices. Additional assistance can be obtained from Environmental Health and Safety.

  • All moderately toxic chemicals will be used inside a chemical hood in the laboratory.
  • All containers will be labeled, with the full chemical name(s) of the reagents contained within, on permanent labels whenever storage of reagents is practiced.
  • All waste containers will be properly and permanently marked with the WMC Hazardous Waste Label (available from EHS), with the full name of all chemicals contained, and will be submitted to Environmental Health and Safety for disposal as needed. Preexisting labels on reused containers should be defaced or covered permanently.
  • All technical and research personnel will handle moderately toxic chemicals and chemicals used in routine procedures in accordance with information contained in Material Safety Data Sheets provided for these chemicals.
  • All employees will read and familiarize themselves with WMC-CU’s “Chemical Hygiene Plan.”

References

United States Occupational Safety and Health Administration “Laboratory Standard” (29CFR 1910.1450) Appendix A, Section (E)(1)

Cassaret and Doull’s Toxicology; 3rd Edition Klaasen Et. Al.; Macmillan Publishing