M256A1 Chemical Agent Detector Kit

The M256A1 Chemical Agent Detector Kit is a capable of detecting and identifying hazardous concentrations of chemical agents in air.

M256A1 Chemical Agent Detector Kit is used to confirm the absence or detect the presence of chemical agents in the air


The M256A1 is used to confirm the absence, or detect the presence, of chemical agents in air. Use of the kit can also determine the type of agent present: nerve, blister, blood Lewisite or Mustard.

M256A1 can be purchased by the kit, or by the case. There are 24 kits in each case.  The kit contains:

  • 12 Sampler-Detectors
  • One booklet of M8 Paper
  • Instruction cards attached by a lanyard to the plastic carrying case.

In 2012, the State of California’s FIRESCOPE Standardized Equipment List, listed the M256A1 as a required item for emergency and Hazmat first responders.

NSN#: 6665-01-133-4964


The sampler-detectors consist of a series of ampoules containing reagents. The ampoules are attached to a small hand-held card. When the ampoules are crushed between the fingers, the liquid reagents can flow down plastic tubes to three distictively shaped test spots.

Each test spot is open to the air and, when the reagent wets the test spot, it interacts with the chemical agent in the air, and will turn the test spot a certain color.

If there is no agent present, then there will be no reaction. The reaction indicates whether a chemical agent is, or is not, present in the air.

For example, a color change in the square area indicates the presence of blister agents, the circular test spot is for blood agents, and the star-shaped field signals nerve agents.

The sampler-detectors identify the following agents:

  • Nerve Agents (V- and G- types)
  • Blister Agents (CX, HD, L)
  • Blood Agents (AC, CK)
  • Lewisite (L)
  • Mustard (H, HD, HN, and HT)
  • The kit does not need to be pointed in a certain direction for it to detect chemical agents, nor does it require a close proximity to work effectively.