Section 4 Hazardous Chemical Safety Requirements for Medical Laboratories

Personnel working in laboratories are exposed not only to various pathogenic microorganisms but also to hazardous goods. It is therefore essential that they fully understand the toxic effects of these hazardous goods, the routes of exposure, and the hazards that may be associated with handling and storing these chemicals. Material safety data sheets (MSDS) or other information on chemical hazards can be obtained from chemical manufacturers or suppliers. In experiments in which these chemicals are used, the above information shall be readily accessible; for example, it may be included as part of a safety manual or operating manual.

I. Routes of Exposure

  1. Inhalation
  2. Contact
  3. Ingestion
  4. Needle stick
  5. Through broken skin

II. Storage of Hazardous Chemicals

Laboratories should keep only the quantity of chemicals needed for day-to-day use. Large quantities of hazardous chemicals shall be stored in specially designated rooms or buildings. They shall be stored separately by classification according to the properties of the chemicals.

III. General Principles Concerning Incompatible Hazardous Chemicals

To avoid fire or explosion, the substances in the left-hand column of Table 5-1 shall be prevented, during storage and handling, from coming into contact with the corresponding substances in the right-hand column of Table 5-1.

Table 5-1 General Principles Concerning Incompatible Chemicals

Class of Chemical Substance Incompatible Chemicals
Alkali metals, such as sodium, potassium, chromium, and lithium Carbon dioxide, chlorine, fire
Halogens Ammonia
Acetic acid, hydrogen sulfide, aniline, sulfuric acid Oxidizers, such as acids, nitric acid, peroxides, permanganates

IV. Toxic Effects of Hazardous Chemicals

Handling certain chemicals or inhaling their vapors can have adverse effects on human health. In addition to well-known toxic substances, many hazardous chemicals are known to have various toxic effects and may cause adverse effects or serious damage to the respiratory system, blood, lungs, liver, kidneys, and gastrointestinal system, as well as other organs and tissues, while some chemicals are carcinogenic or teratogenic.

Some soluble vapors are toxic when inhaled. In addition to the many serious effects mentioned above, exposure may also result in damage to human health that cannot be immediately recognized, which may include poor coordination, drowsiness, and similar symptoms, and may increase the likelihood of accidents.

Long-term repeated contact with many liquid organic solvents may cause skin damage, possibly due to the degreasing effect of organic solvents; allergic and corrosive symptoms may also occur.

V. Explosive Hazardous Chemicals

Azides are commonly used as antimicrobial agents in solutions. Because a slight impact can cause a violent explosion of copper azide, azides should not come into contact with copper or lead (such as sewage pipes and plumbing fixtures).

Ether becomes extremely unstable after aging and drying to form crystals, and may explode.

When perchloric acid dries on woodwork, brickwork, or fibrous materials, it will explode and cause a fire upon impact.

Picric acid and picrates explode when heated and subjected to impact.

VI. Hazardous Chemical Spills

Most manufacturers of laboratory chemicals issue schematic diagrams describing the handling of chemical spills. Appropriate diagrams shall be posted in a prominent position in the laboratory, and the following articles shall be provided:

  1. Chemical spill handling kit
  2. Protective equipment, such as heavy-duty rubber gloves, overshoes or rubber boots, and gas masks
  3. Shovel and dustpan
  4. Forceps for picking up broken glass
  5. Mop, and cloths and paper for wiping
  6. Buckets
  7. Soda ash or sodium bicarbonate for neutralizing acids and corrosive chemicals
  8. Sand (for covering alkaline spills)
  9. Non-combustible cleaning agents
  • When a large chemical spill occurs, the following measures shall be taken:
  1. Evacuate personnel from the scene through the relevant safety officer
  2. Pay close attention to personnel who may have been contaminated
  3. If the spilled material is flammable, extinguish all open flames, shut off the gas in the room and in adjacent areas, open windows (when possible), and switch off electrical appliances that may produce electric sparks
  4. Avoid inhaling vapors produced by the spilled material
  5. If it is safe to do so, start the ventilation equipment
  6. Provide the articles necessary for cleaning up the spill

VII. Compressed Gases

Information concerning compressed gases is given in Table 5-2.

Table 5-2 Storage of Compressed Gases and Liquefied Gases

Container Storage Requirements
Compressed gas cylinders They shall be securely fixed (for example, chained) to a wall or a sturdy laboratory bench, so as to ensure that cylinders will not move because of natural disasters. Caps must be fitted during transport, and cylinders shall be transported using a handcart. Large-capacity cylinders shall be stored in suitable facilities at a certain distance from the laboratory. The storage location shall be locked and appropriately marked. They shall not be placed near radiators, open flames, or other heat sources, or near electrical appliances that may produce electric sparks, nor shall they be placed in direct sunlight.
Small, single-use gas cylinders Must not be incinerated