Editing Isocyanate (section)

==== Occupational exposure limits ====
Exposure limits can be expressed as ceiling limits, a maximal value, short-term exposure limits (STEL), a 15-minute exposure limit or an 8-hour time-weighted average limit (TWA). Below is a sampling, not exhaustive, as less common isocyanates also have specific limits within the United States, and in some regions there are limits on total isocyanate, which recognizes some of the uncertainty regarding the safety of mixtures of chemicals as compared to pure chemical exposures. For example, while there is no OEL for HDI, NIOSH has a REL of 5&nbsp;ppb for an 8-hour TWA and a ceiling limit of 20&nbsp;ppb, consistent with the recommendations for MDI.<ref>{{Cite web |url=https://www.cdc.gov/niosh/npg/npgd0320.html |title=CDC – NIOSH Pocket Guide to Chemical Hazards – Hexamethylene diisocyanate |website=www.cdc.gov |access-date=2018-12-08}}</ref>
{| class="wikitable sortable"
|+ Methylene bisphenyl isocyanate (MDI)
! Organization (region)
! Standard
! Value
|-
| OSHA (USA)
| Ceiling limit
| 20&nbsp;ppb<ref name="auto1">{{Cite web |url=https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TABLEZ1 |title=1910.1000 TABLE Z-1 Limits for Air Contaminants |publisher=Occupational Safety and Health Administration |website=www.osha.gov |language=en |access-date=2018-11-24}}</ref>
|-
| NIOSH (USA)
| Recommended exposure limit (REL) – ceiling limit
| 20&nbsp;ppb<ref name=":0">{{Cite web |url=https://www.cdc.gov/niosh/npg/npgd0413.html |title=Methylene bisphenyl isocyanate |publisher=CDC |access-date=2018-11-24}}</ref>
|-
| NIOSH (USA)
| Recommended exposure limit (REL) – TWA
| 5&nbsp;ppb<ref name=":0" />
|-
| ACGIH (USA)
| Threshold limit value (TLV)
| 5&nbsp;ppb<ref name=":1">{{Cite book |title=MDI and TDI: Safety, Health and the Environment |last1=Allport |first1=D. C. |last2=Gilbert |first2=D. S. |last3=Outterside |first3=S. M. |publisher=John Wiley & Sons, LTD |year=2003 |isbn=978-0-471-95812-3 |location=England |page=346}}</ref>
|-
| Safe Work (Australia)
| All isocyanates – TWA
| 0.02&nbsp;mg/m<sup>3</sup><ref name=":2">{{Cite web |url=https://www.safeworkaustralia.gov.au/system/files/documents/1702/guide-to-handling-isocyanates.pdf |archive-url=https://web.archive.org/web/20181125074012/https://www.safeworkaustralia.gov.au/system/files/documents/1702/guide-to-handling-isocyanates.pdf |archive-date=2018-11-25 |url-status=live |title=Guide to handling isocyanates |last=Safe Work Australia |access-date=2018-11-21}}</ref> (approximately 2.5&nbsp;ppb for comparison)
|-
| Safe Work (Australia)
| All isocyanates – STEL
| 0.07&nbsp;mg/m<sup>3</sup><ref name=":2" /> (approximately 10&nbsp;ppb for comparison)
|-
| Heath & Safety Executive (UK)
| All isocyanates – TWA
|0.02&nbsp;mg/m3<ref name=":3">{{Cite book|title=EH40/2005 Workplace exposure limits|last=HSE|publisher=The Stationery Office|year=2018|isbn=978-0-7176-6703-1|location=United Kingdom|page=17}}</ref>
|-
| Heath & Safety Executive (UK)
| All isocyanates – STEL
| 0.07&nbsp;mg/m<sup>3</sup><ref name=":3" />
|}
{| class="wikitable sortable"
|+ Toluene-2,4-diisocyanate (TDI)
! Organization (region)
! Standard
! Value
|-
| OSHA (USA)
| Ceiling limit
| 20&nbsp;ppb<ref name="auto1"/>
|-
| NIOSH (USA)
| Recommended exposure limit (REL)
| [none]<ref>{{Cite web |url=https://www.cdc.gov/niosh/npg/npgd0621.html |title=Toluene-2,4-diisocyanate |publisher=CDC |access-date=2018-11-24}}</ref>
|-
| ACGIH (USA)
| Threshold limit value (TLV)
| 5&nbsp;ppb<ref name=":1" />
|-
| ACGIH (USA)
| Ceiling limit
| 20&nbsp;ppb<ref name=":1" />
|}