Chemical hazards

Safety in the laboratory

The importance of safety in the laboratory cannot be overemphasized. Most laboratory accidents can be prevented using proper techniques and common sense. Following safe practices in the laboratory requires a personal commitment and concern for others. An unsafe act may also harm an innocent bystander without harming the person who performs the act.

Safety standards and governing agencies

The US government created a system of safeguards and regulations under the Occupational Safety and Health Act of 1970. This system affects nearly every worker in the United States because the regulations apply to all businesses with one or more employees (the regulations are discussed in detail in Chapter 4). Two programs have been mandated by the Occupational Safety and Health Administration (OSHA) to ensure the safety of personnel working in clinical laboratories. One covers occupational exposure to chemical hazards; the other covers exposure to bloodborne pathogens.

The CDC also has established recommendations and resources in Standard Precautions and Transmission-Based Precautions as they relate to specimen collection. Standard precautions apply to the care of every patient, regardless of diagnosis, and assume that blood and body fluids may be infectious. Transmission-based precautions add extra measures on top of standard precautions for patients known or suspected to be infected with a pathogen spread by contact, droplet, or airborne routes.

Chemical hazards

The clinical laboratory may have chemicals that are flammable, caustic, and potentially poisonous. Exposure to these dangerous chemicals can occur by breathing in fumes, direct absorption by contact with the skin, ingestion, direct contact with a mucous membrane, or entry through a cut, abrasion, or burn in the skin. OSHA is involved in regulating the standards directed at minimizing occupational exposure to hazardous chemicals in laboratories. OSHA’s Hazard Communication Standard (HCS; known as the employee “right to know” rule) was enacted in 1983 and expanded to cover all industries by 1987. It ensures that laboratory workers are made fully aware of the hazards associated with their workplace. The law requires the development of a comprehensive plan to put in place safe practices throughout the laboratory regarding chemicals. All workers must be provided with information and training.

Safety data sheet

A safety data sheet must also be on file for all chemicals used in the laboratory. OSHA requires the manufacturer of the chemicals to make these sheets available, usually as a package insert or online. Employers must ensure that SDSs are readily accessible to employees. SDSs supply information about chemical safety and hazard information in case of an accident, spill, or fire to the user or emergency personnel.

Since June 2015, OSHA has required all SDSs to use a uniform 16-section format. The sections most relevant to laboratory staff are:

• Section 1. Identification
• Section 2. Hazard(s) identification
• Section 4. First-aid measures
• Section 7. Handling and storage
• Section 8. Exposure controls/personal protection
• Section 13. Disposal considerations
• Section 14. Transport information
• Section 15. Regulatory information

Sections 12 through 15 are regulated by agencies other than OSHA and are required of the manufacturers, not the employees. The remaining sections (composition, fire-fighting measures, accidental release, physical/chemical properties, stability and reactivity, toxicologic information, and other information) round out the full 16-section format, which every SDS must follow in the same order.

Proper chemical handling, storage, and disposal procedures

In the POL, the most common hazardous chemicals are as follows:

• Sodium hypochlorite, commonly known as bleach, which is used for disinfecting laboratory work areas
• CaviWipes and glutaraldehyde, which are disinfectants
• Acetone and dyes, which are used for staining slides

It should be noted that all of these disinfectants and dyes are available in premixed sprays or wipes to reduce chemical exposure during dilution.

Common guidelines have been developed to reduce the risks associated with handling and storing chemicals in the clinical laboratory:

• Date the chemical containers when they are first opened and first received.
• Keep the laboratory doors closed at all times.
• Only use chemicals that you have been trained to use.
• Store large bottles of acids on low shelves. Store flammable substances away from sources of ignition.
• If a chemical produces toxic or flammable vapors, work under a fume hood that exhausts air to the outside.

Chemical waste is regulated by state and federal laws. Chemicals must be disposed of in a safe manner and according to the laws. Chemicals should be disposed of following state and federal guidelines. General recommendations have been established for chemical waste disposal:

• Check the Safety Data Sheet for disposal considerations.
• Keep chemicals separated. Mixing chemicals can create toxic vapors and mixtures.
• Ensure the chemical waste is correctly identified and labeled.
• Contact a disposal company that handles chemical waste. The disposal company will transfer the chemical waste to the disposal site.

CLIA-waived boundary: a CCMA may perform CLIA-waived tests but is not permitted to handle chemical waste disposal decisions or interpret hazard classifications independently - those responsibilities fall to trained laboratory personnel and the SDS/disposal company on file.

Chemical labels

Chemical labels are workplace safeguards. Chemicals should be tightly sealed and properly marked with the original manufacturer’s labels. A hazard identification system, developed by the National Fire Protection Association (NFPA), provides information at a glance on the potential health, flammability, and chemical reactivity hazards of materials. This identification system consists of four small, diamond-shaped, colored symbols grouped into a larger diamond shape.

• The top diamond is red and indicates flammability (the potential to catch on fire).
• The diamond on the left is blue and indicates a health hazard such as a dangerous inhalant or corrosive acid.
• The diamond on the right is yellow and indicates a reactivity or stability hazard. An example of reactivity is mixing two incompatible chemicals, such as bleach with ammonia, which produces toxic chloramine gas. (Bleach, or sodium hypochlorite, is a base, not an acid - the danger comes from the two chemicals reacting with each other, not from an acid-base pairing.)
• The bottom diamond is white and provides special hazard information using specific symbols, such as OX (oxidizer), W (reacts with water), and SA (simple asphyxiant).

The four-color system also indicates the severity of the hazard by using numbers imprinted in the red, blue, and yellow diamonds from 0 to 4, with 0 representing no hazard and 4 representing an extremely hazardous substance.

Position anchor: red = top = flammability, blue = left = health, yellow = right = reactivity, white = bottom = special hazard. The 0-4 severity scale applies to the red, blue, and yellow diamonds only.

First aid for chemical exposures

Prompt medical attention must be given to victims of chemical exposure. The SDS provides first-aid measures that untrained responders should give to individuals with a chemical exposure. Exposure routes include inhalation, skin and eye contact, and ingestion. Some SDSs provide recommendations for immediate medical care and special treatments needed.

General guidelines for chemical exposures include the following:

• With an accidental exposure of the skin, rinse the affected area under running water for at least 5 minutes. Remove any contaminated clothing.
• If chemicals are splashed in the eyes, flush the eyes with water from an eyewash station for a minimum of 15 minutes.