---
title: "Trimethyl phosphite (121-45-9): exposure limits and sampling"
url: https://analyt-mtc.com/tools/hazard-search/trimethyl-phosphite-121-45-9/
lang: en
alternates:
  en: https://analyt-mtc.com/tools/hazard-search/trimethyl-phosphite-121-45-9/
  de: https://analyt-mtc.com/de/tools/gefahrstoffsuche/trimethyl-phosphite-121-45-9/
---

Hazard search

# Trimethyl phosphite

CAS number

121-45-9

Also known as

Methyl phosphite · Phophorous acid, trimethyl ester · Trimethoxy phosphine

## UK workplace exposure limits

| Limit | Value | Applies to |
| --- | --- | --- |
| 8-hour TWA | 2 ppm |  |
| 8-hour TWA | 10 mg/m³ |  |

## Sampling methods

Our data hold no sampling method for this substance.

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)