This resource does not replace the Occupational Health and Safety Act (OHSA) and its regulations and should not be used as or considered legal advice. MLITSD Inspectors will apply and enforce the OHSA and its regulations based upon the facts as they may find them in a workplace.

Overview

The isocyanates found in body fillers, base coats, clear coats and wind shield replacement adhesives used in auto body shops are a combination of:

  • toluene diisocyanate (TDI)
  • methylene bisphenyl isocyanate (MDI)
  • hexamethylene diisocyanate (HDI)
  • isophorone diisocyanate (IPDI)
  • methylene bis (4-cyclohexylisocyanate)
  • methyl isocyanate
  • ethyl isocyanate
  • phenyl isocyanate (in coating and adhesives)
  • polymeric isocyanates

Health effects

Inhalation of mists or vapours containing isocyanates can cause serious health effects. Workers may become sensitized to, or come in contact with, isocyanates either by breathing in the vapours or through skin contact. Sensitization, after an initial exposure to isocyanates, results in acute allergic reactions to further exposure.

Once a person is sensitized, exposure at even very low levels can result in severe breathing difficulties. Exposure to isocyanates can also result in irritation of the respiratory tract, skin, eyes and in some cases, loss of lung function.

Sources in the workplace

Workers in auto body shops may be exposed to isocyanates when:

  • applying isocyanate-based body fillers
  • spraying base coats and clear coats
  • installing windshields with polyurethane adhesives

Spraying is especially hazardous because the mist produced can easily be inhaled where there are no engineering controls and proper respiratory protection is not in place.

Actions for workplace parties

Substitution

Where possible, substitute isocyanates with non-isocyanate containing body fillers (for example, polyester) and base coats.

Ventilation

Spraying with materials containing isocyanates should be done inside a booth designed for paint spraying and equipped with adequate mechanical ventilation. Body filling with materials containing isocyanates should also be done inside the booth whenever practical. If body filling and windshield replacement are done outside the booth, they should be done in a well-ventilated area.

The booth fan should be left running after spraying has ended until all overspray has been removed. The ventilation equipment, such as a booth fan and filters, must be maintained and operated in such a manner that the face velocity and ventilation rates in the booth meet the manufacturer’s specifications.

Respiratory protection

Provide respiratory protection that is appropriate in the circumstances when workers are spraying materials that contain isocyanates. Refer to the legal requirements below for more information on appropriate respiratory protection.

Skin and eye protection

Avoid skin and eye contact with isocyanates. At minimum, use chemically resistant gloves and appropriate eye protection to prevent skin contact. Wear chemically resistant, hooded coveralls when spraying. Review the Safety Data Sheet (SDS) and consult the personal protective equipment (PPE) supplier or manufacturer when selecting PPE.

Review the SDS for first aid measures, which include the following:

  • If hardener gets in the eyes, flush with clean, lukewarm, low-pressure water for 15 minutes, occasionally lifting the lids. Obtain medical help immediately.
  • If hardener gets on the skin, wash the affected area with soap and water. If possible, rub with a half-and-half mixture of isopropyl alcohol (rubbing alcohol) and water. Do not use this mixture to flush the eyes. Remove contaminated clothing immediately.
  • In case of inhalation, move to a clean air area and obtain medical help immediately.
  • In case of ingestion, call 911 and the Ontario Poison Control Centre 1-800-268-9017.

Other actions

Spills may be neutralized by covering with an absorbent material, such as sawdust vermiculite, and soaking for several hours with a mixture of nine parts water and one-part isopropyl alcohol before disposing. Water alone can be used but it takes longer to neutralize the isocyanate.

Do not wear contaminated clothing even if it is dry. Decontaminate clothing by soaking it in a mixture of nine parts water, one-part isopropyl alcohol and some liquid detergent. Contaminated equipment, including respirators, should be thoroughly decontaminated with the same mixture. Water alone can be used but it takes longer to neutralize the isocyanate.

Train workers on:

  • the hazards of isocyanates
  • work practices
  • personal protective equipment, including the selection care, use, limitations, fit, storage and maintenance of respirators
  • hygiene practices
  • spill clean-up

Sample isocyanate control program occupational health and safety checklist

A sample auto body shop isocyanate control program checklist summarizes the measures that must be included in the control program to protect the health and safety of workers and includes provisions for:

  • engineering controls
  • personal protective equipment (including a written respiratory protection program if workers require or request a respirator)
  • work practices
  • hygiene practices and facilities
  • medical surveillance
  • exposure monitoring
  • record keeping
  • spill clean-up
  • worker training

Legal requirements

The following outlines key legal requirements under the Occupational Health and Safety Act (OHSA) and regulation regarding isocyanates in the workplace.

The OHSA includes an obligation for employers and supervisors to take every precaution reasonable in the circumstances for the protection of a worker in the general duties for employers and supervisors under sections 25, 27 and includes general duties for workers in section 28. Ontario Regulation 490/09 – Designated Substances applies to every employer and worker at auto body shops where isocyanate materials are used.

Joint health and safety committee

Under clause 9 (2) (c) of the OHSA, the shop is required to have a joint health and safety committee if isocyanates are produced, used, handled or stored there and a worker is likely to be exposed to isocyanates. Under section 19 of O. Reg. 490/09, the employer must assess the exposure or likelihood of exposure of a worker to isocyanates in the workplace and make a written record of that assessment.

Isocyanate control program

If the assessment shows that a worker is likely to be exposed to isocyanates, and their health may be affected by the exposure, the shop must have an isocyanate control program in place. The program must meet all the requirements under section 20 of O. Reg. 490/09.

As part of the isocyanate control program employers are required to offer medical surveillance to workers in accordance with the Code for Medical Surveillance for Designated Substances in Ontario Regulation 490/09 (2019). Workers are not required to participate in a medical surveillance program, unless they consent to do so as indicated in subsection 28 (3) of the OHSA.

Employers must limit the level and duration of worker exposure to hazardous biological or chemical agents, including isocyanates, in accordance with section 4 of Regulation 833 – Control of Exposure to Biological or Chemical Agents and section 16 of Ontario Regulation 490/09 – Designated Substances.

Occupational Exposure Limits

The Occupational Exposure Limits (OELs) for isocyanate monomers HDI (hexamethylene diisocyanate), IPDI (isophorone diisocyanate), MDI (methylene bisphenyl isocyanate), TDI (toluene diisocyanate) are:

  • time-weighted average (TWA): 0.005 ppm (TWA means the average airborne concentration of a biological or chemical agent to which a worker may be exposed in a work day or work week)
  • ceiling (C) limit: 0.02 ppm (C means the maximum airborne concentration of a biological or chemical agent to which a worker may be exposed at any time)

There is no OEL for polymeric isocyanates.

Respiratory protection equipment

While spraying materials that contain isocyanates, the worker must always wear either:

  • a NIOSH Type C airline respirator with a full facepiece, hood or loose fitting facepiece/visor operated in positive pressure mode
  • a self-contained breathing apparatus with a full facepiece operated in positive-pressure mode

The respiratory protection equipment must meet the following key requirements:

  • The air supply system must supply breathing air and provide enough capacity to maintain a positive pressure and required flow in each respirator and hood.
  • The air supplied to respirators must be taken from a clean air area.
  • Purity of compressed breathing air for respirators must meet CSA Standard Z180.1:19 (R2019), Compressed Breathing Air and Systems (2019).
  • Compressed breathing air from an oil-lubricated compressor must have a continuous carbon monoxide monitor equipped with audible and visual alarms that activate at 5 parts per million, calibrated according to the manufacturer’s specifications.

The following types of respiratory protection should not be used since they do not provide adequate protection:

  • half-mask air-supplied respirators, even if operated in a positive-pressure mode
  • organic vapour cartridge respirators
  • all types of air-supplied respirators operated in demand mode

The employer must develop (in writing) and implement a respiratory protection program that includes:

  • respirator selection
  • care
  • use
  • limitations
  • fit
  • maintenance
  • worker training
  • instruction

In auto body shops and most other workplaces, employers must ensure there is appropriate hazardous product labelling, availability of SDSs and WHMIS training as required by sections 6-8, 10 and 17 of Regulation 860 – Workplace Hazardous Materials Information System (WHMIS).

Contact us

If you need more information, please contact us:

  • 1-877-202-0008 on Monday to Friday, from 8:30 a.m. to 5 p.m.
  • by email at webohs@ontario.ca.