Chemical cartridge respirator limits for organic vapors

JUN 4, 1990

MEMORANDUM FOR: REGIONAL ADMINISTRATORS

ATTN: ARA'S FOR TECHNICAL SUPPORT

THRU: LEO CAREY Director Office of Field Program

FROM: THOMAS J. SHEPICH Director Directorate of Technical
Support

SUBJECT: Use of Chemical Cartridge Respirators

On February 26, the National Institute for Occupational Safety and Health (NIOSH) distributed a "Respirator Information Notice on Chemical Cartridge Respirators" which stated that ~~since OSHA has revised the permissible exposure limits (PEL) for toxic air contaminants listed in Table Z of 1910.1000,~~ NIOSH has decided to eliminate the maximum use concentrations (MUC) labeling requirement for all approved chemical cartridges under the provision of [42 CFR 84.257] (copies attached).

[This document was edited on 03/30/99 to strike information that no longer reflects current OSHA policy.]

The NIOSH notice has also eliminated the labeling requirements on cartridges for protection against the exposure to organic vapors. We have received numerous inquiries concerning this issue. Since OSHA does not have specific standards for the majority of organic compounds listed in Table Z of 1910.1000, the elimination of the MUC may cause overexposure because many of these contaminants have inadequate odor warning properties. In order to ensure that the organic vapor cartridges are used properly, the attached guidelines should answer most questions when you receive inquiries concerning this issue.

Attachment

GUIDELINES ON THE USE OF CHEMICAL CARTRIDGES FOR

PROTECTION AGAINST ORGANIC VAPOR EXPOSURE

1. Use Limitation:

Use of the cartridges is limited to the lowest of the three air contaminant concentrations determined by the following:

a. Immediately dangerous to life or health (IDLH) concentration.

b. 1,000 parts per million (ppm).

c. The maximum use limit (MUL) which is 10 times the OSHA permissible exposure limit (PEL).

2. These organic vapor cartridges are approved for respiratory protection against organic vapors with definite odor warning properties, meaning that the air contaminant must have a distinctive odor at concentrations at or below the permissible exposure limit established by OSHA for the air contaminant, and the odor warning properties are not affected by olfactory fatigue.

3. The use of chemical cartridges for protection against an air contaminant without definite odor warning properties is acceptable only when the use is permitted in specific OSHA health standards (such as acrylonitrile), when the cartridge has an approved end- of-service-life indicator (such as mercury), or when the cartridge breakthrough time is available based on the following test conditions:

a. Challenge concentration: 10 times the PEL.

b. Air Flow: 32 liters per minute continuously.

c. Relative humidity: 85 to 90%.

d. Temperature: 20 to 25 degree Celsius.

The breakthrough time should be calculated as the mean of at least three samples at a 95% confidence level. Unless the cartridge desorption information indicates that there is no significant desorption from overnight storage, the cartridge should be replaced at the beginning of each shift or prior to the experimental breakthrough time, whichever comes first.

4. Many respirator manufacturers have a list of air contaminants for which the use of chemical cartridges for respiratory protection is not recommended regardless of concentration and time of exposure. Some examples are:

Acrolein, aniline, arsine, bromine, carbon disulfide, carbon monoxide, dimethyl aniline, dimethyl sulfate, hydrogen cyanide, hydrogen fluoride, hydrogen selenide, hydrogen sulfide, methanol, methyl bromide, methyl chloride, isocyanates (MDI, TDI, etc.), nickel carbonyl, nitrobenzene, nitrogen oxides, nitroglycerine, nitromethane, ozone, phosgene, phosphine, phosphorous trichloride, stibine, and vinyl chloride.

The manufacturer's recommendation should be closely followed for chemical cartridge selection. Since the above list is not complete, consult with the respirator manufacturer for additional information.

[Separate NIOSH information notice reproduced on OSHA page; omitted here.]