Author: FFP Ai Bot

TOLEDO — The chemical that has been leaking from a damaged tank in north Toledo since Tuesday night is glycidyl methacrylate, often shortened to GMA. The U.S. Environmental Protection Agency, the City of Toledo and the Toledo-Lucas County Health Department have all named it. Below is a plain-language look at what GMA is, what happens to it once it gets into the air, water and soil, and what health agencies say it can do to the body.

For the latest on the evacuation zone, the 57 people treated and the cleanup, see FFP’s ongoing coverage: Toledo chemical leak: evacuation zone cut to a quarter mile as tank release slows.

What happened in Toledo

Toledo Fire and Rescue responded around 10 p.m. Tuesday, Oct. 20, to a release of glycidyl methacrylate from an intermodal tank of about 5,500 gallons near 1266 Progress Ave., the MC Tank Terminal, according to the U.S. EPA’s incident page. The EPA said Wednesday that the tank had been compromised and that “the chemical within the tank is completing a reaction,” and the city decided the safest course was to let that reaction finish.

The city first ordered a 1-mile evacuation, then a 3-mile shelter-in-place early Wednesday. Both were later scaled back. As of Thursday, Oct. 22, the evacuation zone was a quarter mile and there was no shelter-in-place order, according to the City of Toledo. The city said the release has slowed significantly and the tank’s temperature keeps falling. WTOL 11 reported that hazmat crews entered the site Thursday afternoon.

Officials have not publicly described the exact chemical reaction inside the tank. An Ohio EPA spokesperson told CNN the release was caused by an “error that occurred when the material was being transferred,” but did not say what the error was.

What is glycidyl methacrylate?

GMA is a colorless liquid with a fruity or ester-like odor, according to the National Institutes of Health’s PubChem database and NOAA’s CAMEO Chemicals database. Its chemical formula is C7H10O3, and its registry number is CAS 106-91-2.

The molecule has two reactive parts:

• A methacrylate group, the same kind of building block used to make acrylic plastics.
• An epoxide ring, a strained three-atom ring of two carbons and one oxygen that reacts easily with other chemicals.

Having both makes GMA useful to manufacturers, and it is also what makes it hazardous.

The International Agency for Research on Cancer (IARC) says GMA is used mainly to make epoxy polymers and vinyl and acrylic resins. Those end up in powder coatings, adhesives, dental sealants and composites, bone composite materials, hydrogel contact lenses and food-contact materials. IARC says exposure to GMA as a raw chemical “is not expected from use of the polymerized products.” In other words, the finished plastics are not the concern. The liquid itself is.

Why a tank of it can turn dangerous

NOAA’s CAMEO Chemicals database, used by hazmat crews, warns that epoxides such as GMA “are highly reactive. They polymerize in the presence of catalysts or when heated. These polymerization reactions can be violent.” PubChem lists heat, peroxides and caustics as triggers for polymerization. Polymerization is the chain reaction that links small molecules into long chains, and it gives off heat. PubChem notes that methacrylate esters are normally sold with a stabilizer, such as hydroquinone, added to keep them from reacting on their own.

NOAA also notes that GMA can react with acids, bases and oxidizing and reducing agents, and that heating it produces irritating vapors. The city has said that as the tank’s pressure drops, so does the risk of an explosion. That is why crews waited for the tank to cool before moving in.

What happens to GMA in the air

It evaporates readily. GMA’s vapor pressure is about 0.42 kilopascals (roughly 3 mmHg) at room temperature, according to PubChem. The International Chemical Safety Card summarized in PubChem warns that “a harmful contamination of the air can be reached very quickly on evaporation of this substance at 20 C” (68 F). Once in the air, GMA is expected to exist entirely as a vapor rather than sticking to dust or particles.

It breaks down in about a day. According to the federal Hazardous Substances Data Bank, as reproduced in PubChem, airborne GMA is broken down mainly by hydroxyl radicals, highly reactive molecules formed in the air by sunlight. The estimated half-life for that reaction is about 17 to 19 hours. A slower reaction with ozone has an estimated half-life of about one day. Both figures are model estimates, not measurements. GMA is not expected to be broken down directly by sunlight.

Smog and ozone. GMA is a volatile organic compound (VOC), and the EPA has been monitoring for VOCs around the evacuation zone. The EPA says VOCs as a group react with nitrogen oxides in sunlight to form ground-level ozone, the main ingredient in smog. No agency has published an estimate of how much, if any, ozone this release produced. FFP did not find any official statement on that question.

Greenhouse gas? GMA is not one of the greenhouse gases the EPA tracks, which are carbon dioxide, methane, nitrous oxide and fluorinated gases. Because it breaks down within about a day, it does not build up in the atmosphere the way long-lived greenhouse gases do.

Odor as a warning. The EPA says GMA “has a strong odor, so people will likely smell it before it reaches hazardous levels.” The city adds that smelling an odor “doesn’t always mean toxic levels of exposure.”

What happens to GMA in water and soil

Water. GMA dissolves moderately in water, about 5 grams per 100 milliliters, according to PubChem. Once dissolved, it tends to stay in the water rather than evaporate back out. HSDB estimates its volatilization half-life at about 140 days for a model river and 1,000 days for a model lake. It does not cling much to sediment.

How long it lasts. GMA does not appear to last long in water. A screening assessment by the Organisation for Economic Co-operation and Development (OECD) found it “readily biodegradable,” meaning it was fully broken down by microbes in a 28-day lab test. The same review found it reacts with water (hydrolysis) with a measured half-life of about 3.7 days at neutral pH. Inside the body, IARC notes, GMA is broken apart by enzymes into glycidol and methacrylic acid.

Fish and other aquatic life. GMA is moderately toxic to aquatic life, according to the OECD review:

• For a small fish called the medaka, the concentration that killed half the test fish was 2.8 milligrams per liter over four days and 1.9 milligrams per liter over 14 days.
• For the water flea Daphnia magna, the highest concentration with no effect on reproduction over 21 days was about 1 milligram per liter.
• The OECD set a “predicted no-effect concentration” for aquatic life of 0.01 milligrams per liter.

GMA’s potential to build up in fish is low, with an estimated bioconcentration factor of 3, according to HSDB.

Soil. HSDB says GMA is expected to have “very high mobility” in soil, meaning it can move through soil easily instead of binding to it. It is expected to evaporate only slowly from moist soil.

What officials have said locally. The City of Toledo says tap water is safe because “the water source is not contaminated” and treatment takes place inside closed, pressurized lines. FFP did not find any official statement on whether GMA reached storm drains, the Ottawa River or soil around the site, beyond the guidance below on produce and playgrounds.

Short-term (acute) symptoms

The City of Toledo describes GMA as “an irritant that can cause burning of the eyes, nose, mouth, and skin.” The city says symptoms of overexposure include:

• Headache
• Dizziness
• Tiredness
• Nausea and vomiting

The International Chemical Safety Card, as reproduced in PubChem, says the substance “is severely irritating to the eyes, skin and respiratory tract.” It lists these signs:

• Breathing it in: cough, sore throat and labored breathing.
• Skin contact: redness, pain and skin burns.
• Eye contact: redness, pain and burns.
• Swallowing it: sore throat, a burning feeling in the throat and chest, and abdominal pain.

Under the globally harmonized hazard labeling system, PubChem’s aggregated company notifications classify the liquid as toxic in contact with skin, harmful if swallowed, able to cause severe skin burns and eye damage, and able to cause an allergic skin reaction.

The American Conference of Governmental Industrial Hygienists (ACGIH), which sets widely used workplace exposure guidelines, describes GMA as “highly toxic by inhalation and highly irritating and corrosive to the skin, eyes, and respiratory tract.” In ACGIH’s summary of animal inhalation studies, damage to the lining of the nose was the most consistent finding.

Dose matters. Whether a person develops symptoms, and how serious they are, depends on how much of the chemical they were exposed to and for how long. Most of the effects described in this article come from workplace settings, liquid contact or laboratory animal studies, often at concentrations far higher than a brief whiff of odor.

Long-term (chronic) effects and cancer

Skin allergy. The International Chemical Safety Card warns that “repeated or prolonged contact may cause skin sensitization.” This means a person can develop an allergic skin reaction that returns with later exposures. PubChem’s hazard summary cites reports of allergic contact dermatitis in workers who used adhesive sealants containing GMA.

Cancer classification. IARC, the World Health Organization’s cancer research agency, classified glycidyl methacrylate in 2019 as “probably carcinogenic to humans (Group 2A), on the basis of sufficient evidence of carcinogenicity in experimental animals and strong mechanistic evidence.” IARC also stated that “the evidence from studies of cancer in humans was inadequate.” IARC stresses that its classifications describe how strong the evidence of a cancer hazard is. They do “not indicate the level of cancer risk associated with exposure at different levels.”

The animal evidence comes largely from two-year inhalation studies in Japan. In those studies, mice and rats breathed GMA vapor for most of their lives, and the animals developed more tumors, including tumors of the nasal cavity, according to ACGIH’s review. IARC’s mechanistic reasoning rests partly on glycidol, which the body forms from GMA. IARC has also classified glycidol as probably carcinogenic to humans.

Other agencies say similar things:

• ACGIH lists GMA as “A2 – Suspected Human Carcinogen.”
• California added GMA to its Proposition 65 list of chemicals known to the state to cause cancer, effective Jan. 27, 2023, according to the state’s Office of Environmental Health Hazard Assessment.
• The European Union’s harmonized classification, as listed in PubChem, rates it Carc. 1B (presumed to cause cancer in humans), Muta. 2 (suspected of causing genetic defects) and Repr. 1B (presumed to harm fertility or the unborn child).

These classifications are based on long-term, repeated exposure in animal studies and on how the chemical acts in cells. None of these agencies has said anything about the cancer risk from a short-term community release like the one in Toledo, and FFP is not drawing that conclusion.

Exposure limits

• OSHA: There is no federal OSHA permissible exposure limit (PEL) for GMA. It does not appear in OSHA’s Occupational Chemical Database.
• NIOSH: GMA is not listed in the CDC/NIOSH Pocket Guide to Chemical Hazards, NOAA’s CAMEO database notes.
• ACGIH: The industrial hygiene group recommends a workplace limit (TLV-TWA) of 0.01 parts per million averaged over an eight-hour shift. It adds notations for skin absorption and skin sensitization, and says worker exposures “by all routes should be carefully controlled to levels as low as possible below the TLV.”
• Emergency guideline levels: NOAA’s CAMEO database lists no federal Acute Exposure Guideline Levels (AEGLs) or other emergency planning levels for GMA.

FFP also checked for an ATSDR ToxFAQs sheet or Medical Management Guidelines, and for an EPA IRIS assessment. FFP found none for glycidyl methacrylate.

What residents should do

The City of Toledo and the Toledo-Lucas County Health Department advise the following:

• Odor outside the zone: If you are outside the evacuation zone and smell an unusual odor, stay indoors, close windows and doors, and turn off ventilation that pulls in outside air.
• Minor symptoms: For mild eye, nose, throat or skin irritation, shower or rinse the affected area and contact a medical professional.
• Serious symptoms: For trouble breathing, nausea and vomiting, dizziness or confusion, call 911 or go to an emergency room.
• Returning home: Air out the house. Wipe down surfaces and vehicle door handles with warm, soapy water. Wash any clothing that may have been exposed. Throw out uncovered food and open pet food.
• Produce: The Ohio State University Extension advises throwing away produce or crops that were outdoors within the 3-mile shelter-in-place zone.
• Driving through: Roll up your windows and recirculate the air inside the vehicle.

Who to call:

• Emergencies: 911.
• Poison control: Call Poison Help at 1-800-222-1222, which connects Ohio callers to a poison center around the clock.
• Health questions: Toledo-Lucas County Health Department, 419-213-4100. Its informational hotline is 419-779-7089.
• Shelter needs: 1-800-RED-CROSS or 211.
• General questions: Engage Toledo, 419-936-2020.

Official updates are posted on the City of Toledo incident page and the EPA’s response page. This explainer gives general information from health and environmental agencies and is not medical advice.

Sources

https://response.epa.gov/site/site_profile.aspx?site_id=17475
https://toledo.oh.gov/news/2026/10/21/hazmat-evacuation-in-north-toledo
https://lucascountyhealth.com/public-health-update-glycidyl-methacrylate-gma-chemical-leak/
https://www.wtol.com/article/news/local/toledo-hazmat-incident-evacuation-zone-reduced-quarter-mile/512-86dc5c3e-29c6-427f-a199-b135923290e8
https://pubchem.ncbi.nlm.nih.gov/compound/7837
https://cameochemicals.noaa.gov/chemical/8709
https://www.iarc.who.int/wp-content/uploads/2019/11/QA_Monographs_Volume-125.pdf
https://www.acgih.org/wp-content/uploads/2023/04/Glycidyl_Methacrylate.pdf
https://hpvchemicals.oecd.org/ui/handler.axd?id=44d6c34e-1889-4efd-a534-47ae7b2986f5
https://oehha.ca.gov/proposition-65/chemicals/glycidyl-methacrylate
https://www.epa.gov/ground-level-ozone-pollution/ground-level-ozone-basics
https://www.epa.gov/ghgemissions/overview-greenhouse-gases
https://www.osha.gov/chemicaldata/search
https://www.poison.org/contact-us
https://thefostoriafreepress.com/toledo-mc-tank-chemical-leak-evacuation-zone-quarter-mile-update/