WEL Substance Profile

Hexavalent Chromium — Workplace Exposure Limit Change

CAS: 18540-29-9 | Notation: Inhalable fraction, carcinogen (IARC Group 1)

Current WES

0.05

mg/m³

New WEL (Dec 2026)

0.005

mg/m³

Change

-90%

reduction

Health Effects

Hexavalent chromium is classified as a Group 1 carcinogen by IARC, meaning there is sufficient evidence that it causes cancer in humans. The primary cancer risk is lung cancer, with studies demonstrating significantly elevated rates among chromate production workers, chromium platers, and stainless steel welders. Beyond carcinogenicity, hexavalent chromium causes severe respiratory effects including nasal septum perforation, chronic rhinitis, and occupational asthma. Skin contact produces characteristic chrome ulcers and allergic contact dermatitis. Kidney damage has been documented in workers with chronic exposure. The genotoxic mechanism of hexavalent chromium means there is no true safe threshold — the WEL represents an acceptable risk level rather than a no-effect level.

Where Exposure Occurs

Stainless steel welding (MIG, TIG, and stick processes)Chrome plating and electroplating operationsSpray painting with chromate-containing primersCutting, grinding, and polishing stainless steelCement manufacturing (chromium is a natural trace element)Leather tanning using chromium salts

What to Do Now

01Commission speciated chromium air monitoring at all workstations where stainless steel is welded, cut, ground, or polished. Standard total chromium monitoring does not distinguish hexavalent chromium from less toxic trivalent chromium. Ion chromatography analysis is required to determine the hexavalent fraction, which is the regulated species.

02Install or upgrade local exhaust ventilation with source capture on all stainless steel welding bays. The 90 per cent reduction in the permissible limit means that welding bays previously compliant under the 0.05 mg/m³ WES are likely to exceed the new 0.005 mg/m³ WEL. Extraction systems must be designed to capture fume at the point of generation before it enters the worker's breathing zone.

03Implement a health surveillance program including baseline and periodic lung function testing, urinary chromium monitoring, and nasal examination for septum perforation. Health surveillance is mandatory for workers exposed to carcinogenic substances and must be conducted by a registered medical practitioner with occupational health expertise.

04Evaluate process substitution opportunities including the use of lower-chromium alloys where design specifications permit, transition from manual welding to robotic or automated processes that remove the worker from the fume plume, and replacement of chromate-containing paints and primers with chromate-free alternatives.

05Develop a written chromium exposure control plan that documents the hazard assessment, control hierarchy, RPE selection and fit-testing schedule, air monitoring program, health surveillance program, and emergency procedures for overexposure events. This plan must be reviewed annually and updated whenever monitoring results indicate a change in exposure patterns.

Monitoring Method

Personal air sampling using a calibrated pump with 37mm mixed cellulose ester filter in a closed-face cassette. Analysis by ion chromatography (IC) following NIOSH Method 7605 for hexavalent chromium speciation. Sampling should cover a full shift with a flow rate of 2 L/min. Results must be reported as hexavalent chromium, not total chromium.

Affected Industries

Metal Fabrication →Auto Body and Spray Painting →

Manage Hexavalent Chromium Compliance

EHS Atlas tracks speciated chromium monitoring data against the incoming 0.005 mg/m³ WEL and automates health surveillance scheduling for exposed workers.