Mechanism - Cyanide (CN-) has a high affinity for Fe3+ and, when inhaled or ingested, reacts rapidly with trivalent iron of cytochrome in mitochondria → inhibition of cellular respiration → Krebs cycle arrest, lactic acidosis, and cell death.
Clinical - Patients present with tachycardia (increased heart rate), headache, drowsiness, hypotension, lactic acidosis, coma, and convulsions. Rapidly fatal (1-15 minutes). Since utilization of oxygen is blocked, venous blood is bright red.
Antidote - Amyl nitrite is used to prevent/reverse binding of CN- to Fe3+ of cytochrome oxidase by providing a large pool of Fe3+ to compete for CN-. Hyperbaric O2: potentiates protective effects of amly nitrite and thiosulfate but has little effect when used alone. Gastric lavarge: to remove any residual toxin in the case of ingestion.
Metabolism - Mitochondrial enzyme rhodanase converts CN- to thiocyanate (which is relatively nontoxic and excreted in urine): S2O32- + CN- → SCN- + SO3^2-.
Notes - Bitter almond odor characteristic of HCN gas.

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Minor Spill Procedures

  • If contaminated with hazadous materials, immediately implement personal decontamination procedures prior to cleaning up the spill.
  • Review MSDS and acutely hazardous material list prior to clean-up.
  • Proper personal protection equipment will be donned during the clean up of all hazardous materials. If laboratory personnel does not have the proper personal protective equipment then contact lab manager or general manager for assistance.
  • Contain spilled material(s) using absorbent pads and/or powders. Paper towels will not be used for containment of spill nor will they be used for clean up.
  • Neutralize spill material(s) using the appropriate neutralizing agent.
  • Clean up neutralized material using dust pan and/or plastic scoop.
  • Place neutralized material in hazardous waste bags. Dispose of as hazardous waste.
  • Wash area where spill occurred with water several times making sure no residue was left behind. Dispose of any towels used as hazardous waste.
  • All emergency equipment shall be decontaminated and stored.
  • All non-disposable personal protective equipment shall be decontaminated and stored.
  • All disposable personal protective equipment and clean up materials shall be disposed as hazardous waste.
  • Always use extreme caution when cleaning up hazardous materials.

Eye Protection

  • Eye protection consists of safety glasses with side shields, goggles or face shield, or full-face respirator.
  • Appropriate eye protection must be worn by all persons, (i.e. laboratory personnel and vistors), in laboratories and areas where hazardous materials, (i.e. chemicals, biological materials, radioactive, particulate, etc.), are used or stored. Visitor safety glasses should be made available at the entrances to all laboratories
  • Eye protection is required whether or not one is actually performing experimental operations.
  • Use the appropriate level of eye protection:
    • Safety glasses with side sheilds provide the minimum protection acceptable for regular use. Safety glasses must meet the American National Standards Institute (ANSI) Standard Z87.1-1998, Standard for Occupational and Educational Eye and Face Protection.
    • Safety splash goggles or face shields should be worn when carrying out operations in which there is potential danger from splashing hazardous materials or flying particulates.
    • Goggles are preferred over regular safety glasses to protect against hazards such as projectiles, as well as when working with glassware under reduced or elevated pressures, when handling potentially explosive componds, (particulary during distillations), and when employing glassware in high-temperature operations.
  • Ordinary prescription glasses do not provide adequate protection. Prescription glasses are not impact or chemical resistant.
  • Contact lenses can increase the degree of harm from chemical vapors or a chemical splash or chemical dust and can interfere with first aid and eye flushing procedures.

Face Protection

  • Face Protection consists of full-face shield, full- face respirator, or impact safety shields.
  • Approprate face proection is required when there is a potential for splashes from hazardous materials, explosions, or flying projectiles.
  • Face protection should be used in conjunction with the appropriate eye, hand, and skin protection.

Hand Protection

  • Employee/ students are required to wear appropriate gloves when an employee has the potential for direct contact with hazardous chemicals, sharp-edged objects, very hot or very cold materials, or any other hazardous materials.
  • Select gloves appropriate for the task. Gloves protect differently for each chemical. Wearing the wrong type of glove can be more hazardous than wearing no gloves at all, if the chemical seeps through, the glove can hold it in prolonged contact with the wear's hand.
  • Most glove manufacturers provide selection guides for the different types of gloves manufactured. The selection guides provide the degradation and permeation characteristics for glove material.
  • Inspect gloves for small holes or tears prior to use.
  • Wash gloves appropriately prior to removing them. Dispose of them appropriately.
  • The use of double gloves can provide multiple line of defense when working with highly toxic or multiple hazard materials.
  • Insulated gloves should be used when working with very hot or very cold materials.
  • Reusable gloves, that might be contaminated with chemicals, must not be removed from the immediate area in which the chemicals are located.
  • In order to prevent the unintentional spread of hazardous substances, remove gloves before handling objects such as doorknobs, telephones, pens, sink knobs and computer keyboard/mouse.
  • Gloves must not be worn in hallways, elevators, or public areas. If hazardous materials must be transported from one area to another, glove one hand to hold the product/apparatus or push cart and use a clean ungloved hand to open doors, press buttons, etc.
  • Replace gloves periodically, depending on the frequency of use and their permeation and degradation characteristics relative to the substance handled.
  • Hands should be washed with soap and water immediatelly after removing gloves.

Foot Protection

  • Appropriate shoes that provide proper protection must be worn where hazardous materials are in use.
  • Open-toed footwear is not appropriate!
  • Sandals, perforated shoes, and cloth shoes do not provide protection against spilled chemicals and must not be worn.

Protective Clothing

  • Employees/students are required to wear lab coats when there is the potential for direct contact with hazardous chemicals, very hot or very cold materials, or any other Hazardous materials.
  • Lab coat is required whether or not one is actually performing experimental operations. Lab coats are worn to protect street clothes from hazardous materials.
  • Appropriate lab coats should be worn and buttoned, with the sleeves rolled down.
  • Clothing that leaves large areas of skin exposed, (i.e. shorts, skirts, etc.), must not be worn where hazardous materials are in use.
  • Apparel providing additional protection, (i.e. nonpermeable laboratory aprons), is required for work with certain hazardous substances.
  • Plastic or rubber aprons can provide good protection from corrosive liquids but can be inappropriate in the event of a fire.
  • Disposable garments, (i.e. shoe covers, bib aprons, hair nets, etc.), that have been used when handling carcinogenic or other highly hazardous chemicals, should be removed without exposing any individual to toxic material and disposed of as hazardous waste.
  • Lab coats must be worn only in the laboratory area and are to be removed upon exiting the laboratory.

Respiratory Protection

  • The primary method for the protection of laboratory personnel from airborne contaminants should be to minmize, through engineering and administrative controls, the amount of such materials entering the laboratory air. When effective engineering and administrative controls, (i.e. chemicals fume hoods or local exhaust snorkels or SOPs), are not possible, suitable respiratory protection should be used after proper training.

Fit Checks

  • Respirators need to be adjusted each time they are put on to ensure the best possible seal.
  • There are two common procedures an employee must perform to check a facepiece seal:
    • Positive Pressure Check
    • Negative Pressure Check

Positive Pressure Check

  • To perform a positive pressure check:
    • Cover the exhalation valve of the respirator.
    • Exhale gently for about 10 seconds. Don't exhale too hard or push the mask into the face or the check will be inaccurate.
  • If the respirator fits, a slight pressure should build up inside it. If air leaks out, the respirator does not fit properly and the seal is inadequate.

Negative Pressure Check

  • To perform a negative pressure check:
    • Cover the filter openings with the palms of hands.
    • Inhale gently and hold a breath for about 10 seconds. Don't push the respirator into the face too hard or the check will be inaccurate.
  • If the facepiece fits correctly, it should collapse slightly inward. If facepiece does not fit correctly, it will not collapse and an air leak will be felt.

Color Code for Chemical Cartidges

  • Each chemical cartridge is coded with a particular color that specifies the contaminant for which it provides protection against. This system was developed to provide the wearer an easy way to identify the correct cartridge for the project.
  • The following is the color code system:
    • White - protects against acid gas contaminants.
    • Black - protects against organic vapor contaminants.
    • Green - protects against ammonia gas contaminants.
    • Blue - protects against carbon monoxide gas contaminants.
    • Yellow - protects against acid gas and organic vapor contaminants.
    • Brown - protects against acid gas, ammonia, carbon monoxide, and organic vapor contaminants.
    • Olive - protects against other vapors and gases not listed.
    • Purple - protects against radioactive materials (except tritium and noble gases).
    • Orange - protects against dusts, fumes, and mists (other than radioactive materials).

Here is a link to the Drexel University Lab Saftey Manual.

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