Advocacy & Safety - breathing road salt

Around Chicago it seems like when it snows an inch they put down two inches of salt. Though not as bad in the city, in the burbs the streets are really white from all the salt. After the salt has dried for a few days and before a rain can wash it away, traffic kicks it up into a white dust, just like a vehicle would kick up dust on a gravel road. Can anyone comment on the health affects of breathing this dust might have on a cyclist?

FYI, I've heard that when riding in the traffic the negative affects of breathing car exhaust are surpassed by the aerobic benefits one receives.

Can anyone comment on the health affects of breathing this dust might have on a cyclist?


Personally, I don't think breathing any kind of dust is good for you, but your lungs are designed to handle a reasonable amount of it and clean themselves out regularly. However, I've also wondered about what road-salt can do to your lungs.

I'd try not to breathe it (if possible.) Maybe find a quieter route until it rains.

I don't know about your lungs, But I hope you are riding your beater, Cloride corrosion of steel sure ain't pretty.

I go through some of the same stuff. But it isn't salt, its ash from that huge wildfire we had down in Cali. I usually just tie a bandana around my mouth/nose or wear one of those white facemask things you can get at hole depot or any other home improvemnt store.

I would not worry so much about the salt, but the small particle matter contained within (road grime). If you live near the ocean you breath moist salt air all day.

You bring up an interesting point about breathing dust. Let me take a few moments below to discuss respiratory hazards, but first let me say some things about Material Safety Data Sheets. You should confirm with the road department that this is in fact common salt, sodium chloride, that they are placing on the roads. Ask them for the MSDS, and also look it up on line (search Google for "MSDS for salt").

Some places use different stuff, and the hazards are different. For instance, salt is not much of a respiratory hazard. It is an irritant, that can irritate the upper respirator tract, but will not reach the air sacs in the lungs. It's not pleasant, but it's also not much of a hazard. We all need salt to survive, and our body has built-in mechanisms of using and disposing of it.

Now, about other dusts. First, in order to be "respirable" dust particles must be very small, somewhere between 0.5 and about 25 microns to get into the lower reaches of the lungs, and the air sacs themselves. Larger particles are filtered out in the nose, the back of the mouth, or the upper respiratory track as they are too big to be carried down deep into the lungs, and simply deposit on the sides of the air tubes. Most particles, even this small, when deposited are "beat out" by something called the muco-cilliary escalator. We have cells in our lungs with cilia on them, and this hair cell beats the mucus above it in one direction--out of the lungs. Most dusts, commonly refered to as "road dust" can readily be beat out of the lungs, unless the person is a smoker or exposed to second-hand cigarette smoke. That stops the "muco-cilliary escalator" in its tracks for hours. The "smokers hack" is caused by a resumption of this process when the smoker goes to bed, and the lungs come back to some similance of "normal" (in fact, it takes some weeks and years to really get the lungs back to "normal").

But, there are some particles that cannot be beat out, and the lungs then form scar tissue in reaction to them. This is the basis of silicosis and asbestosis, as silica dust and asbestos fibers cannot be removed from the lungs.

What I'm getting at is that some roads are now being covered with sand (a form of silica), with quartz rock (crushed rock with quartz in it), and even with mine tailings (this happened in Douglas County, where the road department got a good price for the material). This stuff, if crushed into respirable sizes, could cause considerable damage to the lungs. I've not seen any studies on the actual composition of dusts in different areas, but sometime if I get time would like to do just that. I think there are some potential public health issues with what we apply to the roads.

John

I would not be too worried about smoke and ash from wildfires, though. As a former wildfire fighter, I've "eaten" enough smoke that if there were lasting effects, I should have known it by now.

Smoke can contain significant quantites of carbon monoxide, though. So those who already suffer from heart disease or breathing disorders could be adversely affected. The CO takes the place of oxygen on the red blood cell, and if there is already a circulatory or respiratory problem, the person could have an oxygen deficit. This would be especially true if the person exerted. CO can also pre-dispose toward a heart attack, probably by this same mechanism.

People in normal health should not worry about it though.

John

You know, I took my own advise and did the Google search. I found the following OSHA Letter of Interpretation. OSHA (the Occupational Safety and Health Administration) regularly responds to written inquires on pertainent topics. I believe this letter came from 1993, and states that in very high concentrations salt does require a respirator because of the irritation. But they are talking about factories where salt is being packaged, for instance. Anyway, here's the letter:


February 25, 1993

The Honorable Richard G. Lugar
United States Senate
Washington, D.C. 20510

Dear Congressman Lugar:

This is in response to your letter dated January 13, to Ms. Frances McNaught of the Department of Labor. Your letter has been forwarded to the Occupational Safety and Health Administration (OSHA) for response.

A constituent of yours, Mr. Harley W. Rhodehamel, wrote to you asking why a material safety data sheet (MSDS) for salt was required by OSHA. We will explain the MSDS requirements of OSHA's Hazard Communication Standard (HCS) briefly for your constituent's benefit, and provide reasons for Sigma Chemical Company's decision to create the MSDS.

OSHA promulgated the HCS, codified as 29 CFR 1910.1200, to ensure that the hazards of all chemicals produced or imported in the U.S. are evaluated, and that information concerning their hazards is transmitted to employers and employees. The standard applies to all hazardous chemicals to which employees may be exposed under normal conditions of use or in a foreseeable emergency. The responsibility for determining whether a product is hazardous belongs to the manufacturer or importer of the chemical -- not OSHA.

OSHA is aware that some manufacturers prepare MSDSs on products that are not necessarily covered by the HCS. It is our understanding that this is done for product liability reasons, to satisfy regulations from several agencies at once (such as DOT's or EPA's requirements), and in response to customer requests for MSDSs on all products regardless of their hazards (sometimes an MSDS will state that the material is not covered by 29 CFR 1910.1200 -- a practice that is encouraged by OSHA). OSHA compliance staff review the quality of MSDSs when complaints are filed by the users of an MSDS and during the course of routine OSHA inspections. This is effective in ensuring that employees are given vital information about the hazards in their workplace.

The HCS exempts a consumer product if it meets the criteria in 29 CFR 1910.1200(b)(6)(vii), which requires that the employer demonstrate that using the consumer product would result in a "duration and frequency of exposure which is not greater than exposures experienced by consumers." In other words, when chemicals which are normally used by a consumer, such as sodium chloride, are used by employees in a manner that is not comparable to typical consumer use, the HCS requires that a hazard determination be done.

Sigma Chemical Company created the MSDS in question for places of work where sodium chloride is used in large quantities, i.e. in industrial settings. Sigma Chemical Company's MSDS provides information that is important for the employer and employee to know. Specifically, when airborne sodium chloride dust is inhaled it can cause respiratory irritation, and at high enough levels employees are to wear a respirator. Further, the MSDS warns the employer that sodium chloride is incompatible with strong oxidizing agents and strong acids, and reacts violently with bromine triflouride and lithium.

As an employer doing business in the State of Indiana, Mr. Rhodehamel may want to contact the Indiana Department of Labor. Under the Occupational Safety and Health Act of 1970, States are permitted to assume responsibility for their own occupational safety and health programs under a plan approved and closely monitored by Federal OSHA; the Indiana Department of Labor operates under such a plan. As a condition of plan approval, States are required to adopt and enforce standards that are either identical to or "at least as effective" as the Federal standards. For information regarding the requirements of Indiana standards, Mr. Rhodehamel may want to contact:

Indiana Department of Labor
1013 State Office Building
100 North Senate Avenue
Indianapolis, Indiana 46204-2287

Telephone: (317) 232-2665

For further information on hazard communication, enclosed is a copy of the OSHA booklet "Chemical Hazard Communication" which explains the standard and employer's responsibility under the rule. We hope this information is helpful. If you have any further questions please contact the Office of Health Compliance Assistance at (202) 219-8036.

Sincerely,



Roger A. Clark, Director
Directorate of Compliance Programs