2B351 Category 2B

Toxic gas monitors and monitoring systems, and their dedicated detecting “parts” and “components” (i.e., detectors, sensor devices, and replaceable sensor cartridges), as follows, except those systems and detectors controlled by ECCN 1A004.c (see List of Items Controlled).

Category 2: Materials Processing

Reasons for control

• CB: Chemical and biological weapons
• AT: Anti-terrorism

Country chart

List-based license exceptions

Items

1. a. Designed for continuous operation and usable for the detection of chemical warfare agents or precursor chemicals controlled by 1C350 'minimum detection limit' of 0.3 mg/m 3; or
2. b. Designed for the detection of cholinesterase-inhibiting activity.

Related controls

See ECCN 2D351 for “software” for toxic gas monitors and monitoring systems, and their dedicated detecting “parts” and “components,” controlled by this ECCN. Also see ECCN 1A004, which controls chemical detection systems and “specially designed” “parts” and “components” therefor that are “specially designed” or modified for detection or identification of chemical warfare agents, but not “specially designed” for military use, and ECCN 1A995, which controls certain detection equipment, “parts” and “components” not controlled by ECCN 1A004 or by this ECCN.

Notes

Technical note: The 'minimum detection limit' of toxic gas monitors or monitoring systems is the lowest detectable concentration of the analyte required to produce a signal greater than three times the standard deviation of the toxic gas monitor's or monitoring system's signal when measuring a blank sample. In the case of toxic gas monitors or monitoring systems having a deadband or programmed zero suppression, the 'minimum detection limit' is the lowest detectable concentration required to produce a reading.

Source: eCFR, version 2026-08-01, retrieved 2026-08-20T04:04:59+00:00.