Laboratory Orientation, Safety Rules, and Chemical Hygiene — Crime Scene / Forensic Technician

Objective. Students will identify all laboratory hazards, locate emergency equipment, and correctly interpret SDS sheets for every chemical used in the course before handling any reagent.

Why Laboratory Orientation Comes First

Before you touch a single reagent, you must know your workspace. A forensic lab contains chemicals that can burn skin, damage lungs, and carry biological hazards. The law requires this training: OSHA's Bloodborne Pathogen standard (29 CFR 1910.1030) mandates exposure-control training before any worker contacts potentially infectious material, and your institution's Chemical Hygiene Plan (CHP) sets the rules for every chemical in the room. Skipping orientation is not just dangerous—it is a regulatory violation that can shut down a program.

The Chemical Hygiene Plan

Every laboratory that uses hazardous chemicals must have a written Chemical Hygiene Plan. Yours is kept in the lab and is always available to you. It identifies the hazards present, describes the controls in place, sets the procedures for handling and storing chemicals, and explains what to do when something goes wrong. Read your CHP before you handle anything. It is your primary reference alongside Safety Data Sheets.

Safety Data Sheets (SDS)

An SDS is a standardized document that tells you everything you need to know to handle a chemical safely. Under the OSHA Hazard Communication Standard (HazCom), every hazardous chemical must have an SDS, and the lab must make them accessible to you at all times. SDS documents follow a 16-section format set by the Globally Harmonized System (GHS):

Section 1 – Identification (product name, supplier)
Section 2 – Hazard identification (signal word, pictograms)
Section 3 – Composition / ingredients
Section 4 – First-aid measures
Section 5 – Fire-fighting measures
Section 6 – Accidental release (spill response)
Section 7 – Handling and storage
Section 8 – Exposure controls / PPE (includes permissible exposure limits)
Section 9 – Physical and chemical properties
Section 10–15 – Reactivity, toxicology, ecological info, regulatory data
Section 16 – Other information (revision date)

For your work, you will consult Sections 2, 4, 6, 8, and 13 (disposal) most often.

Course Reagents and Their Key Hazards

Ninhydrin reacts with amino acids to produce a purple color (Ruhemann's purple), useful for developing latent fingerprints on porous surfaces. It is a skin and eye irritant; always use it inside a fume hood and wear nitrile gloves and safety glasses.

Amido black is a protein stain used to develop bloody prints. It is dissolved in methanol or acetic acid solutions—both flammable and irritating. Use in the fume hood; no open flames nearby.

Luminol is a chemiluminescent reagent that reacts with trace blood. The reagent itself has low acute toxicity, but working solutions often contain sodium hydroxide (caustic) or hydrogen peroxide (oxidizer). Handle with gloves and eye protection.

Crystal violet (gentian violet) is used in some fingerprint and microbiology applications. It is a potential mutagen; minimize skin contact, wear gloves, and dispose of waste according to your CHP.

Phenolphthalein (Kastle-Meyer reagent) is a presumptive blood test chemical. Solutions are prepared in ethanol—flammable. Phenolphthalein itself is classified as a possible carcinogen; limit exposure, use in ventilated areas, and wear gloves.

Personal Protective Equipment (PPE)

PPE is your last line of defense—engineering controls (fume hoods, closed containers) and work-practice controls come first. In this lab you will wear:

Lab coat – protects skin and clothing from splashes
Nitrile gloves – required for all chemical and biological material handling; change gloves between tasks and whenever torn
Safety glasses – minimum eye protection at all times in the lab
Face shield – required when pouring or working with concentrated reagents or potential splash

Never wear open-toed shoes. Tie back long hair. Remove gloves before touching door handles, phones, or your face.

Emergency Equipment Locations

During your lab tour you will locate and physically touch each item:

Eyewash station – for 15 minutes of continuous flushing after any eye exposure
Safety shower – for large chemical splashes to the body
Fire extinguisher – know the PASS technique (Pull, Aim, Squeeze, Sweep)
Fume hood – always have the sash at the marked operating height
First-aid kit – for minor cuts; for anything serious, call emergency services
Spill kit – contains absorbent material, neutralizers, and waste bags
Chemical storage cabinets – flammables in a listed flammable cabinet; acids and bases segregated

Bloodborne Pathogen Awareness

Forensic evidence frequently involves human blood and other potentially infectious materials (OPIM). Under 29 CFR 1910.1030, you must treat all biological evidence as if it is infectious. Use nitrile gloves, avoid touching your face, and place sharps only in approved sharps containers—never recap a needle by hand. Report any needlestick or splash to your instructor immediately and document it.

Incident Response: The Three Scenarios

Chemical splash to eyes or skin: Alert a labmate, go to the eyewash or safety shower immediately (15 minutes for eyes), remove contaminated clothing, and notify the instructor. Fill out an incident report.

Broken glass with biological material: Do not pick up glass with bare hands. Use tongs or a brush and dustpan. Place glass in a puncture-resistant sharps container. Treat the area as a bloodborne pathogen spill—use your spill kit and appropriate disinfectant.

Reagent fume exposure: Move the affected person to fresh air immediately. If symptoms persist, call emergency services. Identify the chemical from the SDS and follow Section 4 first-aid guidance. Document the incident.

All incidents, however minor, must be documented. Documentation protects you, your labmates, and the chain of custody for any evidence that may have been affected.

Key terms10

Chemical Hygiene Plan (CHP)A written program required by OSHA that describes the hazards in a laboratory and the procedures, equipment, and work practices used to protect workers from those hazards.

Safety Data Sheet (SDS)A standardized 16-section document that provides detailed hazard, handling, PPE, and emergency information for a hazardous chemical, required under OSHA's HazCom standard.

Globally Harmonized System (GHS)An international framework that standardizes the classification and labeling of chemicals, including the 16-section SDS format and pictogram system adopted by OSHA.

Permissible Exposure Limit (PEL)The maximum airborne concentration of a substance to which a worker may be exposed, as set by OSHA; found in SDS Section 8.

Bloodborne PathogenA microorganism present in human blood or other potentially infectious materials (OPIM) that can cause disease in humans; regulated under OSHA 29 CFR 1910.1030.

Fume HoodA ventilated enclosure that draws airborne chemical vapors away from the worker; used whenever a reagent produces harmful or flammable vapors.

NinhydrinA chemical reagent used to develop latent fingerprints on porous surfaces by reacting with amino acids in sweat residue to produce a purple color.

LuminolA chemiluminescent reagent that reacts with trace amounts of blood to produce a blue glow, used to detect the presence of blood at crime scenes.

Personal Protective Equipment (PPE)Wearable equipment—including gloves, lab coat, safety glasses, and face shield—used to minimize worker exposure to chemical, biological, and physical hazards.

Kastle-Meyer ReagentA phenolphthalein-based solution used as a presumptive test for blood; a color change to pink in the presence of hydrogen peroxide indicates a positive result.

In class: Guided tour of the lab: students locate eyewash stations, fire extinguisher, fume hood, first-aid kit, spill kit, and chemical storage cabinets, then sketch a floor plan with each safety feature labeled. · SDS scavenger hunt: each student pulls the SDS for five assigned reagents (ninhydrin, amido black, luminol, crystal violet, phenolphthalein) and completes a standardized summary form listing PPE required, exposure limits, and disposal instructions. · Tabletop scenario: instructor presents three simulated lab incidents (chemical splash, broken glass with blood, reagent fume exposure) and students discuss correct response steps, then role-play the response including incident documentation.
Materials: Lab coat, nitrile gloves (multiple sizes), safety glasses, face shield, SDS binder for all course reagents, OSHA Bloodborne Pathogen standard (29 CFR 1910.1030) handout, laboratory Chemical Hygiene Plan, floor plan worksheet
Check: Students score 80% or higher on a 25-question written safety quiz covering SDS interpretation, PPE selection, spill response, and emergency procedures; and correctly identify all emergency equipment locations on the labeled floor plan.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.