Definitions of Hazard Assessment

Following are definitions for terms commonly encountered throughout this guide.

change control:
The management process for requesting, reviewing, approving, carrying out, and controlling changes to agreed-upon deliverables or operational boundaries. It is sometimes referred to as “change management”.

chemical exposure hazard:
A chemical for which there is evidence that acute (immediate) or chronic (delayed) health effects may occur in an exposed population. Exposure is related to the dose (how much), the duration and frequency of exposure (how long and how often), and the route of exposure (how and where a material gets in or on the body), whether through the respiratory tract (inhalation), the skin (absorption), the digestive tract (ingestion), or percutaneous injection through the skin (accidental needle stick). The resulting health effects can be transient, persistent, or cumulative; local (at the site of initial contact with a substance), or systemic (after absorption, distribution, and possible biotransformation, at a site distant from initial contact with a substance).

chemical hygiene officer:
From the Occupational Safety and Health Administration (OSHA) Laboratory Worker Standard, an employee who is designated by their employer, and who is qualified by training or experience, to provide technical guidance in the development and implementation of the provisions of the chemical hygiene plan. This definition is not intended to place limitations on the position description or job classification that the designated individual shall hold within the employer's organizational structure.

Chemical Safety Levels (CSLs):
Defined levels of hazard (1 through 4), based on a risk assessment conducted by a qualified individual:

  • CSL Level 1: Minimal health or physical hazard from chemicals. No concentrated acids or bases, toxics, carcinogens, or teratogens. Less than 4 liters of flammable liquids. No fume hood required and no general ventilation rate specified. Typical examples include: temperature-controlled rooms; K–12 science teaching and demonstration labs; research labs with chemical usage in prepackaged kits; or less than 500 milliliters (mL) of chemicals with the Globally Harmonized System (GHS) “danger” signal words, laser labs (below Class 2B), and microscopy rooms.
  • CSL Level 2: Low health or physical hazard from chemicals. Small amounts, less than 1 liter, of concentrated reagent strength acids or bases, possesses none or limited amounts of toxic or high hazard materials. Less than 40 liters of flammable liquids stored. May need a fume hood for specific activities. Typical examples include: undergraduate chemistry or biochemistry teaching and demonstration labs, and standard biomedical research labs.
  • CSL Level 3: Moderate chemical or physical hazard. Lab work with concentrated acids, bases, toxic, other high hazard chemicals, or cryogenic liquids. Carcinogens or reproductive toxins are handled. Corrosive, flammable, or toxic compressed gases are present in cabinets or fume hoods. Larger volumes (> 40 liters) of flammable liquids are stored in the lab. High hazards in limited quantities may be in the lab with Environmental Health and Safety (EHS) approval (for example, hydrofluoric acid, pyrophoric chemicals, or cyanides). Labs are fume hood or local exhaust intensive. Some uses of a glove box for air or water reactive chemicals. Examples include: chemistry research, pharmacology, chemical engineering, and pathology labs, as well as other chemical intensive research labs.
  • CSL Level 4: High chemical or physical hazard. Work with explosives or potentially explosive compounds, or frequent use of larger quantities of pyrophoric chemicals. Use of large quantities or high hazard materials with significant potential for Immediately Dangerous to Life and Health (IDLH) conditions in the event of uncontrolled release or foreseeable incident. Use of glove box for pyrophoric, or air or water reactive chemicals.

PIs and lab managers need to establish the upper limit on the quantity of high hazard materials that are used. For example, use of more than 5 grams of a pyrophoric material, or 150 mL of 2 molar t-butyllithium (in pentane) could be considered larger quantities.

consequence:
A possible result or outcome of an uncontrolled hazard.

exposure:
The concentration or amount of a particular agent (chemical, biological, electrical, electromagnetic field (EMF), or physical) that reaches a target organism, system, or subpopulation in a specific frequency for a defined duration.

failure modes and effects analysis (FMEA):
An evaluation of the means that equipment can fail or be used improperly, and the effects this failure can have on the process.

fault tree analysis (FTA):
A graphical model that illustrates combinations of failures that will cause one specific failure of interest. It is a deductive technique that uses Boolean logic symbols to break down the causes of an event into basic equipment or human failure.

Globally Harmonized System (of classification and labeling of chemicals) [commonly known as GHS]:
A system used internationally to provide standard criteria for classifying chemicals, according to their health, physical, and environmental hazards. It uses pictograms, hazard statements, and the signal words “Danger” and “Warning” to communicate hazard information on product labels and safety data sheets in a logical and comprehensive way.

hazard:
A potential for harm. The term is often associated with an agent, condition, or activity (a natural phenomenon, a chemical, a mixture of substances, a process involving substances, a source of energy, or a situation or event) that if left uncontrolled, could result in an injury, illness, loss of property, or damage to the environment. Hazards are intrinsic properties of agents, conditions, or activities.

hazard analysis:
A term used to express the complete process of hazard identification, evaluation, and control.

hazard control:
A barrier, such as a device, measure, or limit, used to minimize the potential consequences associated with a hazard.

hazard evaluation:
The qualitative and, whenever possible, quantitative description of the inherent properties of an agent or situation having the potential to cause adverse effects. The definition of “hazard characterization” is adapted from the World Health Organization (WHO).

hazard identification:
The identification of the type and nature of adverse effects from an agent, operation, or equipment, which has an inherent capacity to cause in an organism, system, or (sub) population.

hazard operability (HazOp) analysis:
A technique whereby a multidisciplinary team uses a described protocol to methodically evaluate the significance of deviations from the normal design intention.

hazard statement:
Assigned within the GHS classification and labeling of chemicals. Hazard statements are standardized phrases describing the hazards of chemical substances and mixtures that can be consistently translated into different languages. As such, they serve the same purpose as the well-known R-phrases, which they are intended to replace. Each hazard statement is designated a code, starting with the letter H and followed by three digits. Statements that correspond to related hazards are grouped together by code number, so the numbering is not consecutive. The code is used for reference purposes (e.g., to help with translations), but it is the actual phrase that should appear on labels and safety data sheets. Note that the hazard statement is based not only on the identity of the chemical, but also on its concentration level in the product being described.

high hazard materials (to consider for used in the application of chemical safety levels):
Can be defined in two ways: (1) materials which pose a high health hazard, and (2) those which pose a high physical hazard. High health hazard materials are substances with high acute toxicity (described below) and those which are known carcinogens as identified by the International Agency for Research on Cancer (IARC) Group 1 and Group 2A agents. Group 1 agents are carcinogenic to humans and Group 2A agents are probably carcinogenic to humans. Materials with the following GHS hazard statements are presumed to be a high physical hazard and subject to a risk assessment of its actual use:

  • H201: Explosive; mass explosion hazard
  • H202: Explosive, severe projection hazard
  • H203: Explosive; fire, blast, or projection hazard
  • H220: Extremely flammable gas
  • H240: Heating may cause an explosion
  • H241: Heating may cause a fire or explosion
  • H242: Heating may cause a fire
  • H250: Catches fire spontaneously if exposed to air
  • H251: Self-heating: may catch fire
  • H252: Self-heating in large quantities; may catch fire
  • H260: In contact with water, releases flammable gases which may ignite spontaneously
  • H270: May cause or intensify fire; oxidizer
  • H271: May cause fire or explosion; strong oxidizer

Immediately Dangerous to Life and Health (ILDH):
Any condition that poses an immediate or delayed threat to life or that would cause irreversible adverse health effects.

Job Hazard Analysis:
A systematic approach to address hazards by looking at a task and focusing on the relationship between the laboratory worker, the task, the tools, and the work environment to identify the hazards and reduce the risks.

laboratory:
A facility where the “laboratory use of hazardous chemicals” occurs. It is a workplace where relatively small quantities of hazardous chemicals are used on a nonproduction basis.

laboratory scale:
Describes work with substances in which the containers used for reactions, transfers, and other substance handling are designed to be easily and safely manipulated by one person. Excludes those workplaces whose function is to produce commercial quantities of materials.

laboratory worker:
Refers to career lab staff, PIs, undergraduate students, graduate students, postdoctoral researchers, volunteers, or visiting scholars.

likelihood:
The probability of occurrence, or how likely the complete sequence of events leading up to a consequence will occur upon exposure to a hazard. This term is often associated with descriptors, such as almost certain, likely, possible, unlikely, and rare.

management of change analysis:
An evaluation of the potential safety consequences of planned changes to experimental apparatus, materials, procedure, location or other key parameters conducted prior to implementation of the proposed changes and how identified risks should be managed.

near-miss:
An event in which an injury or loss did not occur, but could have. The conditions of the event are often readily identified as precursors to an accident or loss. These events, which are sometimes referred to as a “near hit,” are indicators that the existing hazard controls, if any, may not be adequate and deserve more scrutiny.

physical hazard:
A class of hazards that include cold, ergonomics, explosions, fire, heat, high pressure, high vacuum, mechanical, nonionizing radiation, ionizing radiation, noise, vibration, and so forth.

Principal investigator (PI):
An individual who has primary responsibility for performing or overseeing research. In some instances, the PI may also be known as the project manager for a research project.

risk:
Takes into account the probability or likelihood that a consequence will occur and the severity of the consequence should it occur. An unlikely hazard with the potential to cause death is a higher risk than an unlikely hazard which would cause temporary illness.

Standard Operating Procedures (SOP):
A written series of steps that can be followed to correctly and safely obtain a desired outcome. In laboratories, SOP are typically developed for repetitive procedures which are known to have associated hazards where injury, property loss, or productivity loss could result if the steps were not followed precisely.

Structured What-if Analysis (SWIF):
A system-based risk identification technique that employs structured brainstorming, using predetermined guidewords and headings (for example, timing, amount, and so forth) in combination with prompts elicited from participants (which often begin with the phrases “What if…” or “How could…”), to examine risks and hazards at a systems or subsystems level.

substance with a high acute toxicity (to consider for use in the application of chemical safety levels):
High acute toxicity includes any chemical that falls within any of the following OSHA-defined categories:

  • A chemical with a median lethal dose (LD50) of 50 milligrams (mg) or less per kilograms (kg) of body weight when administered orally to certain test populations.
  • A chemical with an LD50 of 200 mg or less per kg of body weight when administered by continuous contact for 24 hours to certain test populations.
  • A chemical with a median lethal concentration (LC50) in air of 200 parts per million (ppm) by volume or less of gas or vapor, or 2 mg per liter or less of mist, fume, or dust, when administered to certain test populations by continuous inhalation for one hour, provided such concentrations or conditions are likely to be encountered by humans when the chemical is used in any reasonably foreseeable manner.
  • Materials which have been assigned a GHS hazard statement, as follows:
    • H300: Fatal if swallowed
    • H310: Fatal in contact with skin
    • H330: Fatal if inhaled

What-if Analysis:
A creative, brainstorming examination of a process or operation.

What-if/HazOp:
A combination of What-if and HazOp techniques, deriving the benefits of both methods for a more comprehensive review.

What-if/HazOp/checklist:
A combination of What-if, HazOp, and checklist analysis techniques, deriving benefits from each methodology for a more comprehensive review.


This collection of methods and tools for assessing hazards in research laboratories is based on the publication, Identifying and Evaluating Hazards in Research Laboratories. The guide was published in 2015 by the Hazard Identification and Evaluation Task Force of the American Chemical Society’s Committee on Chemical Safety in response to a recommendation from the U.S. Chemical Safety Board.