---
title: "Phosphoric acid (7664-38-2): exposure limits and sampling"
url: https://analyt-mtc.com/tools/hazard-search/phosphoric-acid-7664-38-2/
lang: en
alternates:
  en: https://analyt-mtc.com/tools/hazard-search/phosphoric-acid-7664-38-2/
  de: https://analyt-mtc.com/de/tools/gefahrstoffsuche/phosphoric-acid-7664-38-2/
---

Hazard search

# Phosphoric acid

CAS number

7664-38-2

Also known as

o-Phosphoric acid · Orthophosphoric acid

## UK workplace exposure limits

| Limit | Value | Applies to |
| --- | --- | --- |
| 8-hour TWA | 1 mg/m³ |  |
| 15-minute STEL | 2 mg/m³ |  |

## Sampling methods

| Method | Sampling | Medium | Analysis | Part numbers |
| --- | --- | --- | --- | --- |
| **NIOSH 7903** | Active (pump) |  | IC | [226-10-03](https://analyt-mtc.com/catalog/product/skc-silica-gel-sorbent-tubes/#part-226-10-03) |
| **NIOSH 7908** / Non-Volatile Acids by IC / [Method document (opens in a new tab)](http://www.cdc.gov/niosh/docs/2003-154/pdfs/7908.pdf) | Active (pump) | Quartz filter | IC-CD | [225-9033](https://analyt-mtc.com/catalog/product/quartz-depth-filters/#part-225-9033) / [225-1](https://analyt-mtc.com/catalog/product/aluminium-respirable-dust-cyclone/#part-225-1) |
| **OSHA ID 111** | Active (pump) |  | IC | [225-3-01](https://analyt-mtc.com/catalog/product/mixed-cellulose-ester-membrane-filters/#part-225-3-01) / [225-1](https://analyt-mtc.com/catalog/product/aluminium-respirable-dust-cyclone/#part-225-1) |
| **OSHA ID 165SG** | Active (pump) |  | IC | [226-10-03](https://analyt-mtc.com/catalog/product/skc-silica-gel-sorbent-tubes/#part-226-10-03) |
| **OSHA ID-111** / Phosphoric acid by IC / [Method document (opens in a new tab)](https://www.osha.gov/sites/default/files/methods/osha-id111.pdf) | Active (pump) | 0.8µm MCE filter in 37mm cassette |  | [225-3-01](https://analyt-mtc.com/catalog/product/mixed-cellulose-ester-membrane-filters/#part-225-3-01) / [225-1](https://analyt-mtc.com/catalog/product/aluminium-respirable-dust-cyclone/#part-225-1) |
| **OSHA ID-165SG** / Acid mists by IC / [Method document (opens in a new tab)](https://www.osha.gov/sites/default/files/methods/osha-id165sg.pdf) | Active (pump) | Silica gel tube (400/200mg) |  | [226-10-03](https://analyt-mtc.com/catalog/product/skc-silica-gel-sorbent-tubes/#part-226-10-03) |

Methods and limits as published by their agencies and summarised by SKC; check the current method and the limit that applies to you before sampling.

Source: [SKC Ltd (UK), Hazard Search, used with SKC's permission (opens in a new tab)](https://www.skcltd.com/hazard-search.html); [SKC Inc. (USA), Sampling Guides, used with SKC's permission (opens in a new tab)](https://international.skcinc.com/sampling-guides/)