| No. | Item | Definition |
|---|---|---|
| 1. | acid | corrosive substance with low pH |
| 2. | aerosol | particles suspended in air |
| 3. | alkali | basic corrosive substance |
| 4. | ammonia | pungent toxic gas or liquid |
| 5. | asbestos | hazardous fibrous mineral |
| 6. | asphyxiant | substance that deprives oxygen |
| 7. | assessment | evaluation of hazards and risks |
| 8. | autoignition | self-ignition without spark |
| 9. | benzene | flammable cancer-causing solvent |
| 10. | biohazard | biological material dangerous to health |
| 11. | bleach | strong oxidizing cleaner |
| 12. | BLEVE | boiling liquid expanding vapor explosion |
| 13. | buddy system | working with a safety partner |
| 14. | carcinogen | cancer-causing substance |
| 15. | caustic | strongly corrosive or burning |
| 16. | chemical | a substance with specific properties |
| 17. | chlorine | toxic greenish gas |
| 18. | combustible | capable of burning |
| 19. | concentration | amount present in a mixture |
| 20. | contamination | presence of dangerous unwanted material |
| 21. | corrosive | able to burn or destroy tissue |
| 22. | decontamination | removal of hazardous contamination |
| 23. | deflagration | rapid burning below sound speed |
| 24. | detection | finding hazardous substances or conditions |
| 25. | detonation | explosive combustion with shockwave |
| 26. | diesel | fuel used in diesel engines |
| 27. | dilution | reducing concentration by adding liquid |
| 28. | dose | amount received by a person |
| 29. | drum | large container for chemicals |
| 30. | encapsulation | fully enclosing protective suit |
| 31. | evacuation | moving people out of danger |
| 32. | exposure | contact with a harmful substance |
| 33. | faceshield | clear shield for face protection |
| 34. | flammable | easily set on fire |
| 35. | flash point | lowest temperature igniting vapors |
| 36. | foam | firefighting blanket of bubbles |
| 37. | formaldehyde | pungent preservative and irritant |
| 38. | fume | fine airborne solid particles |
| 39. | gasoline | motor fuel from petroleum |
| 40. | gloves | hand protection equipment |
| 41. | goggles | protective eyewear |
| 42. | hazard | something that can cause harm |
| 43. | hazmat | hazardous materials work or gear |
| 44. | hot zone | highest contamination area |
| 45. | identification | determining what substance is present |
| 46. | IDLH | immediately dangerous to life |
| 47. | incompatibility | dangerous reaction between substances |
| 48. | ingestion | taking a substance by mouth |
| 49. | inhalation | breathing in a substance |
| 50. | injection | entry through puncture or wound |
| 51. | irritant | substance causing inflammation or discomfort |
| 52. | kerosene | combustible petroleum fuel |
| 53. | lead | toxic heavy metal |
| 54. | leak | unintended escape of substance |
| 55. | LEL | lowest ignitable vapor level |
| 56. | liquefied gas | gas stored as liquid |
| 57. | mercury | toxic metallic element |
| 58. | mist | tiny liquid droplets in air |
| 59. | mitigation | actions reducing incident severity |
| 60. | mixture | combination of different substances |
| 61. | monitoring | checking for hazardous conditions |
| 62. | mutagen | substance causing genetic change |
| 63. | neutralization | making acid or base harmless |
| 64. | NFPA 704 | hazard diamond rating system |
| 65. | off-gassing | release of vapors from material |
| 66. | outgassing | giving off trapped gases |
| 67. | overpack | outer container for damaged package |
| 68. | oxidizer | substance that supports combustion |
| 69. | PEL | permissible exposure limit |
| 70. | permeation | passing through protective material |
| 71. | pesticide | chemical used to kill pests |
| 72. | petroleum | crude oil or related products |
| 73. | pH | measure of acidity or alkalinity |
| 74. | placard | hazard sign on transport unit |
| 75. | plume | airborne cloud from a release |
| 76. | ppm | parts per million concentration |
| 77. | radioactive | emitting harmful ionizing radiation |
| 78. | recon | initial hazard assessment survey |
| 79. | release | escape of hazardous material |
| 80. | residue | material left behind after release |
| 81. | risk | chance of harm |
| 82. | runoff | contaminated liquid flowing away |
| 83. | sampling | collecting material for analysis |
| 84. | SDS | safety data sheet |
| 85. | shelter-in-place | stay indoors for protection |
| 86. | solution | uniform mixture of substances |
| 87. | solvent | liquid that dissolves substances |
| 88. | spill | accidental release of material |
| 89. | teratogen | substance harming fetal development |
| 90. | TLV | recommended exposure guideline |
| 91. | toxic | poisonous or harmful to life |
| 92. | toxicity | degree of poisonousness |
| 93. | UEL | highest ignitable vapor level |
| 94. | UN number | four-digit hazard identification code |
| 95. | vapor | gas form of a substance |
| 96. | volatile | evaporates readily |
| 97. | warm zone | decontamination support area |
| 98. | washdown | rinsing off contamination |
| 99. | waste | unwanted material requiring handling |
| 100. | zone control | managing access by area |