1.5 Laboratory Safety: Chemical, Fire, Electrical, Biological, and Physical Hazards

Laboratory Safety: Chemical, Fire, Electrical, Biological, and Physical Hazards

Laboratory safety carries 5% of the Clinical Chemistry blueprint, and safety principles also appear in microbiology, blood banking, and histopathology questions. In the Philippines, workplace safety is governed by the Occupational Safety and Health Standards Law (RA 11058, 2018) and its implementing rules (DOLE Department Order No. 198, series of 2018). Fire safety follows the Fire Code of the Philippines (RA 9514), and health care waste follows the DOH health care waste management manual covered in the microbiology biosafety section. This section covers chemical hazard communication, chemical storage and spills, fire and electrical safety, compressed gases, biological exposures, radiation, and ergonomics.

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1. Hazard Communication

Safety Data Sheets (SDS)

Every hazardous chemical in the laboratory must have a Safety Data Sheet that staff can reach during their shift. Under the Globally Harmonized System of Classification and Labelling of Chemicals (GHS), the SDS has 16 standard sections, including identification, hazard identification, composition, first-aid measures, firefighting measures, accidental release measures, handling and storage, exposure controls and personal protective equipment, physical and chemical properties, stability and reactivity, and toxicological information.

GHS Labels

• A GHS label shows a product identifier, a signal word ("Danger" for more severe hazards and "Warning" for less severe ones), hazard statements, precautionary statements, supplier information, and pictograms.
• Examples of pictograms: flame (flammables), flame over circle (oxidizers), exploding bomb (explosives), corrosion (skin corrosion and eye damage), gas cylinder (gases under pressure), skull and crossbones (severe acute toxicity), exclamation mark (irritants and less severe toxicity), health hazard silhouette (carcinogens, mutagens, respiratory sensitizers), and environment (aquatic toxicity).

NFPA 704 Diamond

The National Fire Protection Association diamond tells emergency responders the hazards of a material at a glance. Each quadrant is rated from 0 (minimal) to 4 (severe):

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2. Chemical Handling, Storage, and Spills

• Storage: Segregate incompatible chemicals. Keep acids away from bases, oxidizers away from flammables and organic materials, and store flammable liquids in an approved flammable-storage cabinet. Store heavy containers and corrosives on low shelves, never above eye level.
• Dilution rule: Always add acid to water, slowly, never water to acid. Adding water to concentrated acid can boil the water locally and spatter acid.
• Fume hoods: Volatile, toxic, or flammable chemicals such as formaldehyde, xylene, and concentrated acids are handled in a chemical fume hood with the sash lowered. Perchloric acid needs a special wash-down hood because it forms explosive perchlorates in ductwork.
• Specific hazards:
  • Sodium azide (a preservative in some reagents) reacts with lead and copper plumbing to form explosive metal azides. Flush drains with large volumes of water if disposal by drain is allowed.
  • Picric acid becomes explosive when dry and must be kept wet.
  • Formaldehyde is a carcinogen and sensitizer, and xylene is a neurotoxic solvent. Exposure is reduced with ventilation and monitored as required.
  • Mercury spills are collected with a mercury spill kit, never with a vacuum cleaner.
• Spills: Alert others, contain the spill, and use the appropriate kit. Acid spills are neutralized with sodium bicarbonate; alkali spills are neutralized with a weak acid such as citric acid or a commercial neutralizer.
• Eye and skin exposure: Flush eyes at an eyewash station for at least 15 minutes, holding the eyelids open. Use a safety shower for large skin splashes and remove contaminated clothing.

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3. Fire Safety

Fire Classes and Extinguishers

A multipurpose ABC dry chemical extinguisher covers most laboratory fires.

RACE and PASS

• RACE: Rescue anyone in immediate danger, sound the Alarm, Contain the fire by closing doors, then Extinguish a small fire or Evacuate.
• PASS: Pull the pin, Aim at the base of the fire, Squeeze the handle, and Sweep from side to side.
• If clothing catches fire: stop, drop, and roll, or use a fire blanket or safety shower.

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4. Electrical Safety and Compressed Gases

• Use grounded (three-prong) plugs, avoid extension cords for permanent equipment, keep liquids away from outlets, and unplug equipment before servicing it. Report frayed cords and equipment that sparks or shocks.
• Electric shock victim: Do not touch the person until the power is off. Turn off the source or move the person with a non-conducting object, then call for help and start resuscitation if needed.
• Compressed gas cylinders: Keep them upright and secured with chains or straps, keep the valve cap on when not in use, move them only on a cylinder cart, and store them away from heat.

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5. Biological Safety and Exposure Response

• Standard precautions treat all blood and body fluids as potentially infectious: gloves, gowns, and eye or face protection as the task requires, hand hygiene, and no eating, drinking, smoking, applying cosmetics, or handling contact lenses in the work area.
• Sharps: Never recap a used needle by hand (use a one-handed scoop technique only when recapping is unavoidable), and place sharps immediately in a puncture-resistant container that is replaced when three-quarters full.
• Needlestick or splash exposure: Wash the wound with soap and water (or flush mucous membranes with water), report immediately, and have the source patient tested with consent. HIV post-exposure prophylaxis should start as soon as possible, ideally within hours and no later than 72 hours. A worker not immune to hepatitis B may need hepatitis B immune globulin and vaccination.
• Biosafety levels, biological safety cabinets, and waste segregation are covered in the microbiology sterilization and biosafety section.

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6. Radiation, Physical Hazards, and Ergonomics

• Radiation: Radioactive materials (now rare in clinical labs since radioimmunoassay was largely replaced) are regulated by the Philippine Atomic Energy Regulatory Authority (PhilATOM). RA 12305 (2025) created PhilATOM and transferred to it the regulatory functions previously held by the Philippine Nuclear Research Institute (PNRI) and the FDA's radiation regulation office. Protection rests on time, distance, and shielding, with personal dosimeters for monitored workers.
• Physical hazards: Centrifuges must be balanced with the lid closed until the rotor stops. Autoclaves, hot plates, and liquid nitrogen require heat- or cold-resistant gloves and face protection.
• Ergonomics: Repetitive pipetting and microscope work cause strain injuries. Adjust chair and microscope height, use electronic or low-force pipettes, and take short breaks.
• Incident reporting: Every accident, exposure, and near miss is reported and documented so the cause can be corrected.