The term immediately dangerous to life or health ( IDLH) is defined by the US National Institute for Occupational Safety and Health (NIOSH) as exposure to airborne contaminants that is "likely to cause death or immediate or delayed permanent adverse health effects or prevent escape from such an environment." Examples include smoke or other poisonous gases at sufficiently high concentrations. It is calculated using the LD50 or LC50. The Occupational Safety and Health Administration (OSHA) regulation (1910.134(b)) defines the term as "an atmosphere that poses an immediate threat to life, would cause irreversible adverse health effects, or would impair an individual's ability to escape from a dangerous atmosphere."
IDLH values are often used to guide the selection of breathing apparatus that are made available to workers or firefighters in specific situations.
The NIOSH definition does not include oxygen deficiency (below 19.5%) although atmosphere-supplying breathing apparatus is also required. Examples include high altitudes and unventilated, .
The OSHA definition is arguably broad enough to include oxygen-deficient circumstances in the absence of "airborne contaminants", as well as many other chemical, thermal, or pneumatic hazards to life or health (e.g., pure helium, super-cooled or super-heated air, hyperbaric or hypo-baric or submerged chambers, etc.). It also uses the broader term "impair", rather than "prevent", with respect to the ability to escape. For example, blinding but non-toxic smoke could be considered IDLH under the OSHA definition if it would impair the ability to escape a "dangerous" but not life-threatening atmosphere (such as tear gas).
The OSHA definition is part of a legal standard, which is the minimum legal requirement. Users or employers are encouraged to apply proper judgment to avoid taking unnecessary risks, even if the only immediate hazard is "reversible", such as temporary pain, disorientation, nausea, or non-toxic contamination.
NIOSH respirator selection logic
Textbook NIOSH recommended for use in IDLH conditions only pressure-demand self-contained breathing apparatus with a full facepiece, or pressure-demand supplied-air respirator equipped with a full facepiece in combination with an auxiliary pressure-demand self-contained breathing apparatus.
IDLH values
- Ca
- NIOSH considers this substance to be a potential occupational carcinogen. Revised values may follow in parentheses.
- N.D.
- Not determined. That is, the level is unknown, not non-existent.
- 10%LEL
- The IDLH value has been set at 10% of the lower explosive limit although other irreversible health effects or impairment of escape due to toxicology exist only at higher levels.
| 75070 | |
| 64197 | |
| 108247 | |
| 67641 (10% Lower explosive limit LEL) | |
| 75058 | |
| 79276 | |
| 107028 | |
| 79061, carcinogenic substance | |
| 107131 | |
| 309002, carcinogenic substance | |
| 107186 | |
| 107051 | |
| 106923 | |
| 504290 | |
| 7664417 | |
| 7773060 | |
| 628637 | |
| 626380 | |
| 62533, carcinogenic substance | |
| 90040 | |
| 104949 | |
| 7440360 | |
| 86884 | |
| 7440382 | |
| 7784421, carcinogenic substance | |
| 86500 | |
| 7440393 | |
| 7440393 | |
| 71432, carcinogenic substance | |
| 94360 | |
| 100447 | |
| 7440417 | |
| 1303862 | |
| 7637072 | |
| 7726956 | |
| 75252 | |
| 106990, (10% Lower explosive limit LEL); carcinogenic substance | |
| 78933 | |
| 111762 | |
| 123864, (10% Lower explosive limit LEL) | |
| 105464 (10% Lower explosive limit LEL) | |
| 540885, (10% Lower explosive limit LEL) | |
| 71363 | |
| 78922 | |
| 75650 | |
| 109739 | |
target="_blank" rel="nofollow"> 1533 | 1189851, carcinogenic substance |
| 2426086 | |
|
target="_blank" rel="nofollow"> 0018 | 109795 |
| 98511 | |
| 7440439, carcinogenic substance | |
| 7440439, carcinogenic substance | |
| 7778441, carcinogenic substance | |
| 1305788 | |
| 76222 | |
| 63252 | |
| 1333864 | |
| 124389 | |
| 75150 | |
| 630080 | |
| 56235, carcinogenic substance | |
| 57749, carcinogenic substance | |
| 8001352, carcinogenic substance | |
| 31242930 | |
| 7782505 | |
| 10049044 | |
| 7790912 | |
| 107200 | |
| 532274 | |
| 108907 | |
| 2698411 | |
| 74975 | |
| 53469219, carcinogenic substance | |
| 53469219, carcinogenic substance | |
| 67663, carcinogenic substance | |
| 600259 | |
| 76062 | |
| 126998, carcinogenic substance | |
| 1333820, carcinogenic substance | |
| cr2m3 | |
| cr3m3 | |
| 7440473 | |
| 65996932, carcinogenic substance | |
| 7440484 | |
| 7440508 | |
| cotdust | |
| 136787 | |
| cresol | |
| cresol | |
| cresol | |
| 123739 | |
| 98828 (10% Lower explosive limit LEL) | |
| 110827 | |
| 108930 | |
| 108941 | |
| 110838 | |
| 542927 (10% Lower explosive limit LEL) | |
| tin-org | |
| 94757 | |
| 50293, carcinogenic substance | |
| 17702419 | |
| 8065483 | |
| 123422 | |
| 334883 (10% Lower explosive limit LEL) | |
|
target="_blank" rel="nofollow"> 0432 | 19287457 |
| 107664 | |
| 84742 | |
| 95501 | |
| 106467, carcinogenic substance | |
| 75718 | |
| 118525 | |
| 75343 | |
| 540590 | |
| 111444, carcinogenic substance | |
| 75434 | |
| 594729 | |
| 76142 | |
| 62737 | |
| 60571, carcinogenic substance | |
| 109897 | |
| 100378 | |
| 75616 | |
| 2238075, carcinogenic substance | |
| 108838 | |
| 108189 | |
| 127195 | |
| 124403 | |
| 121697 | |
| 300765 | |
| 68122 | |
| 57147, carcinogenic substance | |
| 131113 | |
| 77781, carcinogenic substance | |
| 528290 | |
| 528290 | |
| 528290 | |
| 534521 | |
| 25321146, carcinogenic substance | |
| 117817, carcinogenic substance | |
| 123911, carcinogenic substance | |
| 92524 | |
| 34590948 | |
| 72208 | |
| 106898, carcinogenic substance | |
| 2104645 | |
| 141435 | |
| 110805 | |
| 111159 | |
| 141786 (10% Lower explosive limit LEL) | |
| 140885, carcinogenic substance | |
| 64175 (10% Lower explosive limit LEL) | |
| 75047 | |
| 100414 (10% Lower explosive limit LEL) | |
| 74964 | |
| 106354 | |
| 75003 (10% Lower explosive limit LEL) | |
| 107073 | |
| 107153 | |
| 106934, carcinogenic substance | |
| 107062, carcinogenic substance | |
| 628966 | |
| 151564, carcinogenic substance | |
| html, carcinogenic substance | |
| 60297 (10% Lower explosive limit LEL) | |
| 109944 | |
| 75081 | |
| 100743 | |
| 78104 | |
| 14484641 | |
| 12604589 | |
| 7782414 | |
| 75694 | |
| 50000, carcinogenic substance | |
| 50000, carcinogenic substance | |
| 64186 | |
| 98011 | |
| 98000 | |
| 556525 | |
| 7782425 | |
| 7440586 | |
| 76448, carcinogenic substance | |
| 142825 | |
| 67721, carcinogenic substance | |
| 1335871 | |
| 110543 (10% Lower explosive limit LEL) | |
| 591786 | |
| 108101 | |
| 108849 | |
| 302012, carcinogenic substance | |
| 10035106 | |
| 7647010 | |
| 74908 | |
|
target="_blank" rel="nofollow"> 0283 | 7664393 |
| 772841 | |
| 7783075 | |
| 7783064 | |
| 123319 | |
| 7553562 | |
| 1309371 | |
| 123922 | |
| 123513 | |
| 123513 | |
| 110190 (10% Lower explosive limit LEL) | |
| 78831 | |
| 78591 | |
| 108214 | |
| 67630 (10% Lower explosive limit LEL) | |
| 75310 | |
| 108203 (10% Lower explosive limit LEL) | |
| 4016142 | |
| 463514 | |
| 7439921 | |
| 58899 | |
| 7580678 | |
| 68476857 (10% Lower explosive limit LEL) | |
| 1309484 | |
| 121755 | |
| 108316 | |
| 7439965 | |
| 7439976 | |
| merc-hg | |
| 141797 (10% Lower explosive limit LEL) | |
| 72435, carcinogenic substance | |
| 79209 (10% Lower explosive limit LEL) | |
| 74997 (10% Lower explosive limit LEL) | |
| 59355758 (10% Lower explosive limit LEL) | |
| 96333 | |
| 109875 (10% Lower explosive limit LEL) | |
| 67561 | |
| 74895 | |
| 110430 | |
| 74839, carcinogenic substance | |
| 109864 | |
| 110496 | |
| 74873, carcinogenic substance | |
| 71556 | |
| 108872 (10% Lower explosive limit LEL) | |
| 25639423 | |
| 583608 | |
| 101688 | |
| 75092, carcinogenic substance | |
| 107313 | |
| 541855 | |
| 60344, carcinogenic substance | |
| 74884, carcinogenic substance | |
| 108112 | |
| 624839 | |
| 74931 | |
| 80626 | |
| 98839 | |
| 12001262 | |
| 7439987 | |
| moly-mo | |
| 100618 | |
| 110918 (10% Lower explosive limit LEL) | |
| 8030306 (10% Lower explosive limit LEL) | |
| 91203 | |
| 13463393, carcinogenic substance | |
| 7440020, carcinogenic substance | |
| 54115 | |
| 7697372 | |
| 10102439 | |
| 100016 | |
| 98953 | |
| 100005 | |
| 79243 | |
|
target="_blank" rel="nofollow"> 0930 | 10102440 |
| 7783542 | |
| 55630 | |
| 75525 | |
| 108032 | |
| 79469, carcinogenic substance | |
| 88722 | |
| 88722 | |
| 88722 | |
| 2234131 | |
| 111659 (10% Lower explosive limit LEL) | |
| 8012951 | |
| 20816120 | |
| 7783417 | |
| 10028156 | |
| 1910425 | |
| 56382 | |
| 19624227 | |
| 87865 | |
| 109660 (10% Lower explosive limit LEL) | |
| 107879 | |
| 594423 | |
| 7616946 | |
| 8002059 (10% Lower explosive limit LEL) | |
| 108952 | |
| 106503 | |
| 101848 | |
| 122601, carcinogenic substance | |
| 100630, carcinogenic substance | |
| 7786347 | |
| 75445 | |
| 7803512 | |
| 7664382 | |
| 7723140.html 7723140 | |
| 10026138 | |
| 1314803 | |
| 7719122 | |
| 85449 | |
| 88891 | |
| 83261 | |
| platinum | |
| 65997151 | |
| cyanides | |
| 74986 (10% Lower explosive limit LEL) | |
| 109604 | |
| 71238 | |
| 78875, carcinogenic substance | |
| 75558, carcinogenic substance | |
| 75569, carcinogenic substance | |
| 627134 | |
| 8003347 | |
| 110861 | |
| 106514 | |
| rhodium | |
| rhodium | |
| 299843 | |
| 83794 | |
| 7782492 | |
| 7783791 | |
| 7631869 | |
| 14808607, carcinogenic substance (25 mg/m3 – cristobalite, tridymite; 50 mg/m3 – crystalline silica) | |
| 7440224 | |
| soapston | |
| fluoride | |
| cyanides | |
| fluoride | |
| 62748 | |
| 1310732 | |
| 7803523 | |
| 8052413 | |
| 57249 | |
| 100425 | |
| 7446095 | |
| 7664939 | |
| 10025679 | |
| 5714227 | |
| 2699798 | |
| 93765 | |
| 14807966 | |
| 7440257 | |
| 3689245 | |
| 13494809 | |
| 7783804 | |
| 107493 | |
| 26140603 | |
| 26140603 | |
| 26140603 | |
| 76119 | |
| 76120 | |
| 79345, carcinogenic substance | |
| 127184, carcinogenic substance | |
| 78002 | |
| 109999 (10% Lower explosive limit LEL) | |
| 75741 | |
| 3333526 | |
| 509148 | |
| 479458 | |
| thallium | |
| 137268 | |
| 7440315 | |
| tin-org | |
| 13463677, carcinogenic substance | |
| 108883 | |
| 584849, carcinogenic substance | |
| 95534, carcinogenic substance | |
| 126738 | |
| 79005, carcinogenic substance | |
| 79016, carcinogenic substance | |
| 96184, carcinogenic substance | |
| 76131 | |
| 121448 | |
| 75638 | |
| 118967 | |
| 78308 | |
| 115866 | |
| 8006642 | |
| 7440611, carcinogenic substance | |
| uranium, carcinogenic substance | |
| vandust | |
| vanfume | |
| 25013154 | |
| 81812 | |
|
target="_blank" rel="nofollow"> 0085 | 95476 |
|
target="_blank" rel="nofollow"> 0084 | 95476 |
|
target="_blank" rel="nofollow"> 0086 | 95476 |
| 1300738 | |
| 7440655 | |
| 7646857 | |
| 1314132 | |
| 7440677 |
| 7782505 |
| 100447 |
| 77781, carcinogenic substance |
| 76062 |
| 75445 |
| 5714227 |
| 29750008 |
| nerve |
| nerve |
| nerve |
| nerve |
| nerve |
See also
- NIOSH air filtration rating
External links
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