Adversarial Injection · Industrial Chemical AI Monitoring · Attack #130

Methacrylonitrile (MAN) Specialty Acrylate Polymer: AI Prompt Injection via ±8 DN Pixel Perturbation — FIRST Methacrylonitrile AI Attack

Methacrylonitrile (MAN, 2-methylacrylonitrile, 2-methyl-2-propenenitrile; CAS 126-98-7; MW 67.09; bp 90.3 °C; flash point 1 °C) is an OSHA Process Safety Management-listed toxic flammable liquid at a threshold quantity of only 250 lbs under 29 CFR 1910.119 Appendix A — one of the lowest flammable/toxic combined TQs in the PSM list — with a NIOSH proposed IDLH of 4 ppm, an ACGIH TLV-TWA of 1 ppm (skin notation indicating significant dermal absorption), and a CERCLA reportable quantity of 100 lbs. Like its structural relative acrylonitrile (AN), methacrylonitrile requires continuous MEHQ (monomethyl ether of hydroquinone) inhibitor maintenance at 200–500 ppm to prevent spontaneous exothermic polymerization; unlike AN (OSHA PSM TQ 10,000 lbs), MAN's 40× lower TQ 250 lbs means that a single drum — 55 US gallons at density 0.80 g/mL = approximately 735 lbs — is nearly three times the PSM threshold quantity. A single ±8 DN adversarial pixel perturbation can suppress a depleted MEHQ reading from 52 ppm (critically deficient) to 350 ppm (apparently compliant), hide an explosive 4.8 vol% MAN atmosphere in a storage building from the pre-alarm setpoint at LEL/2 = 1.0%, or conceal a tank temperature of 68 °C approaching the runaway polymerization regime. Glyphward detects all three attack surfaces at threshold 36 before any image reaches a downstream AI inference call.

Methacrylonitrile is produced in small volumes as a specialty monomer for applications requiring both the nitrile group (polarity, H-bonding, CN IR signature at 2,237 cm⁻¹) and the methyl-substituted double bond (steric bulk, higher glass transition temperature Tg compared to polyacrylonitrile). End uses include pH-responsive hydrogel synthesis (poly-MAN co-polymers with acrylic acid), RAFT (reversible addition-fragmentation chain transfer) controlled polymerization libraries, and specialty copolymers for ion exchange membranes in electrochemical separations. Evonik Industries and specialty distributors supply MAN in drum and IBC quantities; global production is estimated below 1,000 tonnes per year, making it an understudied hazard in the specialty chemical safety literature despite its PSM listing. The flash point of 1 °C — only 1 °C above the freezing point of water — means MAN at ambient temperature in most geographic locations and seasons is above its flash point and presents a persistent vapour cloud hazard in storage buildings. NIOSH's proposed IDLH of 4 ppm is based on analogy with acrylonitrile (IDLH 85 ppm at TLV 2 ppm) adjusted for the approximately 4× higher estimated acute mammalian toxicity of MAN at equivalent concentrations. AI monitoring systems managing MAN storage and handling must treat every sensor display with adversarial scepticism.

Why MAN Specialty Polymer Storage Is Disproportionately Vulnerable to Pixel Manipulation

Three structural characteristics make methacrylonitrile storage and handling unusually susceptible to adversarial DCS display attacks. First, the PSM threshold of 250 lbs is so low that typical storage configurations — a single 55-gallon drum (735 lbs) or a 275-gallon IBC (2,200 lbs) — exceed the PSM TQ by factors of 3 to 9. This means the OSHA PSM Programme's full requirements (Process Hazard Analysis, Pre-Startup Safety Review, Management of Change, Incident Investigation, Emergency Planning) apply to even the smallest specialty chemical storage configuration. Any AI monitoring system managing the MAN storage area is directly within the PSM regulatory scope. Second, the flash point of 1 °C means the vapour pressure–ambient temperature relationship keeps MAN above its flash point at virtually all non-arctic conditions, producing a continuous vapour generation rate that challenges building ventilation systems and creates persistent explosive atmosphere risk whenever containment is compromised. Third, the MEHQ inhibitor chemistry is identical to VDC and AN — the same free-radical scavenging mechanism, the same depletion kinetics under heat and trace oxygen, and the same compressed timeline from inhibitor exhaustion to runaway polymerization. A DCS bar displaying a healthy 350 ppm MEHQ on a 0–600 ppm scale requires only a 99-px upward pixel shift to hide a 52 ppm actual inhibitor concentration — a shift achievable within JPEG compression noise on a rendered DCS display image.

Surface 1 — MEHQ Inhibitor Concentration in MAN Storage Tank (Downward Attack)

The MEHQ inhibitor photometric analyser output for the MAN storage tank is displayed on a 200 px vertical DCS bar spanning 0 to 600 ppm. The pixel scale is 200 px ÷ 600 ppm = 0.333 px per ppm. At the actual MEHQ concentration of 52 ppm — 74% below the minimum safe specification of 200 ppm — the rendered pixel position is 52 × 0.333 = 17.3 px from the bottom of the bar. The adversarial perturbation shifts this pixel cluster upward by 99.4 px to position 116.7 px. The AI inference engine reads the concentration as 116.7 ÷ 0.333 = 350 ppm — well within the 200–500 ppm design range. No MEHQ dosing alarm is generated; no inhibitor replenishment batch is scheduled.

At 52 ppm MEHQ, the inhibitor is below the minimum threshold where free-radical scavenging can suppress localized chain initiation events in MAN. Uninhibited MAN polymerization proceeds autocatalytically: each chain initiation event generates heat (approximately 61 kJ/mol MAN), which increases the radical generation rate, which further depletes the remaining MEHQ in a positive feedback loop. At the flash point of 1 °C, the polymerization exotherm does not need to raise the MAN to a high temperature before creating a vapour cloud — MAN is already above its flash point at ambient temperature. The temperature rise from the exotherm increases the vapour pressure (BP 90.3 °C), accelerating vapour generation into the storage building atmosphere and pushing the building concentration from background levels toward the LEL of 2.0%.

Surface 2 — MAN Vapour Concentration in Storage Building (Upward Attack)

The fixed-point catalytic bead vapour detector in the MAN storage building is displayed on a 200 px vertical DCS bar spanning 0 to 8 vol% (covering the LEL 2.0% and UEL ~6.8% with margin). The pixel scale is 200 px ÷ 8 vol% = 25 px per vol%. At the actual vapour concentration of 4.8 vol% — 240% of LEL 2.0%, well within the explosive range — the rendered pixel position is 4.8 × 25 = 120 px from the bottom of the bar. The adversarial perturbation shifts this pixel cluster downward by 110 px to position 10 px. The AI inference engine reads the concentration as 10 ÷ 25 = 0.4 vol% — below the LEL/2 pre-alarm setpoint of 1.0% and far below the LEL action alarm at 2.0%. No ignition-source isolation order is issued; no emergency ventilation override is activated.

At 4.8 vol% MAN in the building atmosphere, the mixture is within the explosive range at every point in the building. MAN vapour density is approximately 2.3× air, causing it to accumulate at floor level where non-Ex electrical components — conduit junction boxes, pump motor starters, floor-level lighting, forklift battery systems — provide reliable ignition sources. The building pre-alarm setpoint of LEL/2 = 1.0% is designed to provide time for ignition-source isolation before the mixture reaches LEL; at 4.8 vol% (4.8× the pre-alarm threshold), the building has been in an explosive state for an extended period. The NIOSH proposed IDLH of 4 ppm simultaneously means workers in the 4.8 vol% (48,000 ppm) MAN atmosphere face an acute inhalation hazard 12,000× the IDLH — both explosion and acute toxicity consequences are present simultaneously.

Surface 3 — MAN Storage Tank Temperature (Upward Attack)

The MAN storage tank skin temperature is displayed on a 200 px vertical DCS bar spanning 0 to 100 °C. The pixel scale is 200 px ÷ 100 °C = 2 px per °C. At the actual tank temperature of 68 °C — indicative of an active polymerization exotherm in progress — the rendered pixel position is 68 × 2 = 136 px from the bottom of the bar. The adversarial perturbation shifts this pixel cluster downward by 92 px to position 44 px. The AI inference engine reads the temperature as 44 ÷ 2 = 22 °C — indistinguishable from ambient temperature. No cooling activation is triggered; no inhibitor emergency dosing is initiated; the polymerization runaway continues undetected.

At 68 °C with depleted MEHQ inhibitor (52 ppm actual, as per Surface 1), the polymerization rate is sufficient to sustain an exotherm that generates more heat than the tank can dissipate through its walls. The positive feedback loop (exotherm → higher temperature → faster polymerization rate → greater exotherm) proceeds toward the MAN boiling point of 90.3 °C. As MAN approaches its boiling point, vapour generation into the headspace accelerates, pressurising the tank. The pressure relief device (PRV or rupture disk) activates, discharging MAN vapour at approximately 1 °C flash point into the building — the same flash fire mechanism as Surface 2, but sourced from the relief device rather than from a tank seal failure. At 68 °C, the tank has been in runaway for an estimated 15–30 minutes; intervention at this stage requires emergency cooling water application to the tank exterior, emergency inhibitor injection, and potential evacuation of the building.

Integrating Glyphward into MAN Storage AI Monitoring Pipelines

The following Python snippet authenticates every MAN storage DCS frame against the Glyphward API before passing it to a downstream safety-monitoring LLM. Three context labels map to the three attack surfaces. A non-clean verdict raises a typed exception routed to the plant's Safety Instrumented System for automatic cooling activation, emergency inhibitor dosing, building evacuation alarm, and ignition-source isolation.

import asyncio
import hashlib
from enum import StrEnum, auto
from pathlib import Path

import httpx

GLYPHWARD_API = "https://api.glyphward.com/v1/scan"
GLYPHWARD_KEY = "gw_live_..."   # set via env var GLYPHWARD_API_KEY
MAN_GLYPHWARD_THRESHOLD = 36

class MANContext(StrEnum):
    MEHQ_INHIBITOR_CONC = auto()   # Surface 1 — downward attack
    BUILDING_VAPOR_CONC = auto()   # Surface 2 — upward attack
    TANK_TEMPERATURE    = auto()   # Surface 3 — upward attack

class AdversarialMANImageError(RuntimeError):
    def __init__(self, surface: MANContext, score: int, frame_hash: str):
        super().__init__(
            f"[Glyphward] MAN adversarial pixel detected on {surface.value}: "
            f"score={score} >= threshold={MAN_GLYPHWARD_THRESHOLD} "
            f"| frame={frame_hash}"
        )
        self.surface = surface
        self.score = score
        self.frame_hash = frame_hash

async def verify_man_frame(frame_path: Path, surface: MANContext) -> dict:
    raw = frame_path.read_bytes()
    frame_hash = hashlib.sha256(raw).hexdigest()
    async with httpx.AsyncClient(timeout=4.0) as client:
        resp = await client.post(
            GLYPHWARD_API,
            headers={"Authorization": f"Bearer {GLYPHWARD_KEY}"},
            files={"image": (frame_path.name, raw, "image/png")},
            data={"context": surface.value, "threshold": MAN_GLYPHWARD_THRESHOLD},
        )
        resp.raise_for_status()
        result = resp.json()
    if result["verdict"] != "clean":
        raise AdversarialMANImageError(surface, result["score"], frame_hash)
    return {"verdict": result["verdict"], "score": result["score"], "hash": frame_hash}

async def safe_man_storage_read(frame_dir: Path) -> list[dict]:
    surfaces = [
        (MANContext.MEHQ_INHIBITOR_CONC, frame_dir / "mehq_inhibitor_man_tank.png"),
        (MANContext.BUILDING_VAPOR_CONC, frame_dir / "man_building_vapor.png"),
        (MANContext.TANK_TEMPERATURE,    frame_dir / "man_tank_temperature.png"),
    ]
    tasks = [verify_man_frame(path, ctx) for ctx, path in surfaces]
    return await asyncio.gather(*tasks)

All three verification calls run concurrently. The MEHQ surface check runs simultaneously with the vapour and temperature checks so that a combined multi-surface attack — in which all three displays are manipulated simultaneously to mask a MAN polymerization runaway — raises three independent typed exceptions rather than a composite alarm. Because the OSHA PSM TQ is only 250 lbs, a missed adversarial attack enabling a fire in the MAN storage area constitutes a direct PSM incident requiring 29 CFR 1910.119(m) investigation and OSHA 300 recordkeeping. The SHA-256 frame hash in each exception provides forensic traceability for PSM incident investigation, including determination of whether the DCS display image was adversarially manipulated before the AI inference call that failed to detect the developing hazard.