Epichlorohydrin

Epichlorohydrin is produced by chlorinating propylene and then treating with a base — a process commercialized by Shell and Dow in the 1940s [1]. Its primary use is as a starting material for epoxy resins: it reacts with bisphenol A (BPA) to form the backbone of nearly all epoxy resins used in coatings, adhesives, electrical laminates (circuit boards), and fiber-reinforced composites [2]. It is also used to make synthetic glycerol, ion exchange resins, and wet-strength paper additives. Annual global production exceeds 1 million tons. Epichlorohydrin is highly volatile and readily absorbed through skin, making worker exposure in epoxy resin manufacturing a significant concern [1]. EPA classifies it as a probable human carcinogen (Group B2) and it appears on both the HAP list and the OSHA-regulated carcinogen list [2].

Occupational inhalation and dermal contact in epoxy resin manufacturing, water treatment chemical production, and paper manufacturing are primary routes [1]. Dermal absorption is particularly important because epichlorohydrin is lipophilic and penetrates skin efficiently without causing immediate irritation warnings [2]. Consumer exposure occurs during application of two-part epoxy adhesives and coatings before the epoxide groups have fully reacted; uncured epoxy components contain residual epichlorohydrin [1]. Water treatment: epichlorohydrin-based flocculants are used in some drinking water treatment plants, and trace residuals reaching consumers are regulated but detectable [2]. Workers who lay epoxy flooring or apply epoxy boat coatings without proper protective equipment are at significant risk [1].

Epichlorohydrin is both directly reactive and metabolically activated to glycidol — another potent alkylating agent [1]. Both forms attack DNA guanine residues, cross-link DNA, and cause sister chromatid exchanges and chromosomal aberrations. Animal studies show renal cortical tumors after inhalation and oral exposure; occupational cohort studies among epichlorohydrin workers show elevated rates of lung and other cancers [2]. Beyond carcinogenicity, epichlorohydrin causes kidney toxicity through reactive metabolite accumulation in renal tubules, and allergic contact dermatitis and sensitization in exposed workers [1]. Epichlorohydrin is also neurotoxic at high acute doses [2].

Epoxy resin production workers, paper mill workers using wet-strength resins, and water treatment plant operators face the highest routine occupational exposure [1]. DIY epoxy users — boat builders, flooring installers, jewelry makers using resin casting — are an underappreciated risk group who often work in home garages with poor ventilation [2]. Workers sensitized to epichlorohydrin develop allergic contact dermatitis that can be disabling and may cross-react with epoxy resins broadly [1]. People with compromised kidney function may be more susceptible to the nephrotoxic effects of chronic low-level exposure [2].

1. When using two-part epoxy products (adhesives, coatings, casting resins), work outdoors or with maximum ventilation; wear nitrile or neoprene gloves — latex does not adequately block epichlorohydrin [1]. 2. Wear safety glasses and avoid skin contact entirely — sensitization from a single significant exposure can cause lifelong allergic reactivity to all epoxy products [2]. 3. Use low-emission, lower-toxicity waterborne epoxy formulations where possible for interior projects. 4. Do not sand or grind cured epoxy surfaces without dust collection and respiratory protection — sanding generates respirable particles [1]. 5. If you experience contact dermatitis from epoxy work, see a dermatologist; patch testing can confirm sensitization and guide avoidance [2]. 6. Professional epoxy applicators should insist on industrial hygiene monitoring and use half-face respirators with organic vapor/P100 cartridges [1].