| Mann in Not | person in danger |
| Manometer | pressure gauge |
| Manometerleitung | pressure gauge hose |
| Manometer-Prüfung | pressure gauge check |
| Manometer-Sichtscheibe | pressure gauge glass |
| Manometervergleichsprüfung | pressure gauge comparison test |
| Maske | mask |
| Maskenanschlussstück | facepiece connector |
| Maskenbeutel | mask bag |
| Maskenbrille | mask spectacles |
| Maskendichtheit | face seal |
| Maskendichtrahmen | Facepiece seal |
| Masken-Helm-Kombination | mask-helmet combination |
| Maskenkörper | mask body |
| Maskenprüfung | mask test |
| Maskentragebüchse | mask carrying box |
| Maskentragetasche | mask carrying bag |
| Materialschädigung | material damage |
| Mayday | MayDay |
| Maximale Arbeitsplatzkonzentration | maximum allowed workplace concentration |
| Mehrbereichgasfilter | multiple gas filter |
| Menschenrettung | rescue of people |
| Methan | methane |
| MHK | mask-helmet combination |
| Mikroorganismen | mircroorganisms |
| Mindestanforderungen | minimum requirement |
| Mindestbetriebsbedingungen | minimum operating conditions |
| Mischgas | mixed gas |
| Mischgasgerät | mixed gas closed-circuit breathing apparatus |
| Mittedruck | medium pressure |
| Mitteldruckleitung | medium pressure connecting tube |
| Mitteldruckprüfung | medium pressure test |
| Mitteldruckstufe | medium pressure stage |
| Mittezeit | midtime |
| Multitypgasfilter | multi-type gas filter |
| Mundstück | mouthpiece |
| Mundstückgarnitur | mouthpiece assembly |
| Mundstückkörper | moutpiece body |
| Mutagene | mutagens |
