Skip to content
Immediate assistance(213) 300-9915
AlertRelief

Was I exposed?

CDC/NIOSH Methyl Methacrylate Exposure Symptoms & Flammable-Vapor Hazard

By AlertRelief Editorial Desk · Reviewed by AlertRelief Editorial Desk · Updated 1d ago

This page summarizes what the CDC's National Institute for Occupational Safety and Health (NIOSH) and OSHA publish about methyl methacrylate (MMA) — the chemical involved in the Garden Grove tank incident — focusing on exposure symptoms and the flammable-vapor hazard. It is general information compiled from cited public sources, not medical advice, and AlertRelief is not a law firm.

NIOSH chemical safety profile

From the NIOSH Pocket Guide to Chemical Hazards and the NIOSH IDLH documentation:

  • Routes of exposure: inhalation, ingestion, and skin and/or eye contact
  • Target organs: eyes, skin, and the respiratory system
  • Symptoms: irritation of the eyes, skin, nose, and throat; dermatitis
  • NIOSH REL / OSHA PEL: 100 ppm (410 mg/m³), time-weighted average (TWA)
  • IDLH: 1,000 ppm
  • Flash point: about 50°F
  • Flammable range: roughly 1.7%–8.2% in air (lower–upper explosive limit)

For the authoritative, complete entry — including measurement methods and personal protective equipment — refer to the NIOSH and OSHA sources above.

Exposure symptoms

The NIOSH Pocket Guide lists MMA as an irritant to the eyes, skin, and respiratory system, with symptoms of irritation of the eyes, skin, nose, and throat, and dermatitis. Seek medical care for difficulty breathing or symptoms that persist, and tell the clinician you may have been exposed.

For a plain-language overview, see what methyl methacrylate is, and for guidance on care, see symptoms and when to see a doctor.

The flammable-vapor hazard

A flash point of 50°F means MMA can release ignitable vapor at ordinary room temperature — it does not need to be heated to become a fire risk. Per NIOSH, it is flammable across a range of about 1.7% to 8.2% in air (its lower and upper explosive limits). In the Garden Grove incident, officials warned the overheating tank could either leak or ignite.

First aid (per NIOSH)

  • Eyes: irrigate immediately
  • Skin: flush promptly with water
  • Breathing effects: respiratory support
  • If swallowed: seek medical attention immediately

For exposure questions, the U.S. Poison Control line is 1-800-222-1222; call 911 for emergencies. This is general information, not a substitute for professional medical care.

If you were near the Garden Grove incident

Sources

Common questions

What are the symptoms of methyl methacrylate (MMA) exposure?

The NIOSH Pocket Guide lists irritation of the eyes, skin, nose, and throat, and dermatitis. Seek medical attention for difficulty breathing or symptoms that persist, and tell the clinician about the exposure. This is general information, not medical advice.

Is methyl methacrylate a flammable vapor?

Yes. Per the NIOSH Pocket Guide, MMA has a flash point of 50°F, meaning it can give off ignitable vapor at typical room temperature, and it is flammable across a range of about 1.7% to 8.2% in air (its lower and upper explosive limits).

What are the NIOSH and OSHA exposure limits for MMA?

The NIOSH recommended exposure limit (REL) and the OSHA permissible exposure limit (PEL) are both 100 ppm (410 mg/m³) as a time-weighted average (TWA). NIOSH lists the level Immediately Dangerous to Life or Health (IDLH) as 1,000 ppm.

What is the first aid for MMA exposure?

NIOSH first aid is to irrigate eyes immediately, flush skin promptly with water, provide respiratory support for breathing effects, and seek medical attention immediately if swallowed. For exposure questions, the U.S. Poison Control line is 1-800-222-1222; call 911 for emergencies. This is not a substitute for professional medical care.

Back to the full incident