pc6300@cbnscs.UUCP (Linda Dunlap - AT&T Network Systems, Columbus OSTC) (10/07/87)
Our Environmental department asked me if there is anything they need to be concerned with regarding the disposal of a large number of 700' and 2400' reels of magnetic tape. They seemed to think there were trace amounts of mercury in them. Can anyone advise? Linda Dunlap - AT&T, Columbus, Ohio cbnscs!pc6300
larry@kitty.UUCP (Larry Lippman) (10/08/87)
In article <276@cbnscs.UUCP>, pc6300@cbnscs.UUCP (Linda Dunlap - AT&T Network Systems, Columbus OSTC) writes: > Our Environmental department asked me if there is anything they need > to be concerned with regarding the disposal of a large number of > 700' and 2400' reels of magnetic tape. They seemed to think there were > trace amounts of mercury in them. Can anyone advise? My organization did a lab study for a toy manufacturer a few years back to determine if there were any materials in magnetic recording tape which could injure a young child if they were to ingest the tape from a broken tape cassette. I won't event begin to speculate what would possess a child do do this. :-) In this day and age, manufacturers of consumer products - especially toys - are concerned to the point of paranoia about product liability. In any event, I am have some familiarity with magnetic recording tape composition as a result of this study. Computer tape does have a different formulation from that of audio tape, but it's close enough for the present discussion. The tape itself (sans magnetic compounds) is a polyester film; chemically, it is (poly) 1,4-butylene terephthalate or (poly) tetramethylene terphthalate. The film also contains small amounts of stabilizers and a coloring agent. While we did not study computer tapes per se, my educated guess is that a 2,400 foot 1/2 inch computer tape with a magnetic coating thickness of 250 microinches will contain approximately one ounce (weight) of magnetic coating material. The magnetic coating material will most likely be a blend of ferric oxide and chromium dioxide, along with a resin which binds the material together and causes adherence to the polyester film. There may also be a small amount of a molybdenum compound (like molybdenum disulfide) as a lubricant. That's it. All of the above compounds in the quantities which may be found in magnetic recording tape are intrinsically safe to the environment. Magnetic recording tape is not "bio-degradeable", but over hundreds of years it will probably depolymerize into powder. There is no mercury or mercury compounds intentionally added to any magnetic recording tape that I am aware of. In our study for the toy manufacturer, we examined about 20 samples of tape from different manufacturers of audio cassettes. We conducted a general analysis for heavy metals by means of AA and ICP spectrophotometric analysis. While we did find traces of heavy metals (including mercury), the amounts were insignificant (in the ppb range); this is no more than would be found by analysis of any common object like say, a paperclip. I suppose I shouldn't say this, but the only possible environmental hazard of magnetic recording tape could result from burning it. At temperatures between 250 and 500 deg C the chromium dioxide would be converted to chromium trioxide, which is a rather corrosive substance. However, the quantities involved in the tape are still rather small, and burning probably represents no worse a scenario than the production of hydrogen chloride by the burning of PVC. So, to sum up: I don't see any potential environmental harm posed by the landfill disposal of magnetic recording tape. There is a slight potential environmental harm posed by incineration of recording tape, but the effects of this can be mitigated by combustion in an incinerator equipped with a waste gas scrubber (pretty common these days). <> Larry Lippman @ Recognition Research Corp., Clarence, New York <> UUCP: {allegra|ames|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry <> VOICE: 716/688-1231 {hplabs|ihnp4|mtune|seismo|utzoo}!/ <> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"
jeffj@sfsup.UUCP (J.S.Jonas) (10/08/87)
[] In article <276@cbnscs.UUCP>, pc6300@cbnscs.UUCP writes: > Our Environmental department asked me if there is anything they need > to be concerned with regarding the disposal of a large number of > 700' and 2400' reels of magnetic tape. They seemed to think there were > trace amounts of mercury in them. Can anyone advise? > > Linda Dunlap - AT&T, Columbus, Ohio cbnscs!pc6300 If you are concerned about environmental impact, why not erase them and sell them to a surplus place (or at least donate them to a college). (Unless they are too beaten up and worn to use.) You can bulk erase them if you are concerned about security. Hasn't your Environmental department heard of recycling and the surplus market? Here in New Jersey, recycling is THE LAW! The landfills are too full. Localities choose what to recycle, usually glass and aluminum. It's an idea whose time has come!
larry@kitty.UUCP (Larry Lippman) (10/09/87)
In article <2166@sfsup.UUCP>, jeffj@sfsup.UUCP (J.S.Jonas) writes: > > Our Environmental department asked me if there is anything they need > > to be concerned with regarding the disposal of a large number of > > 700' and 2400' reels of magnetic tape. > > If you are concerned about environmental impact, why not erase them > and sell them to a surplus place (or at least donate them to a college). > You can bulk erase them if you are concerned about security. > Hasn't your Environmental department heard of recycling and the > surplus market? The truth of the matter is that computer tape designed for digital recording makes a rather unsatisfactory audio tape. Not that 1/2 inch computer tape slit to audio size won't work, mind you, but the audio quality will be poor. The reason is that digital data recording is a "saturation" type of recording whereby there are only 0's and 1's written on the tape, with such binary elements being determined by signals of proper magnetic polarity. The magnetic oxide material on digital computer tapes has a B-H magnetic response curve which is optimized for such saturation recording. Not the same type of B-H curve found on audio tape. Incidently, there is (or pretty much was) a 1/2 inch tape which was not that bad when slit for audio use. This is tape designed for IRIG-spec analog instrumentation recorders which were extensively used in military and aerospace applications during the 1950's through 1970's. These recorders did record signals in analog form, and their tape had decent B-H curves. Such analog instrumentation recorders are still used today, but they are rapidly being replaced by digital signal processing which uses digital recorders. HUGE amounts of surplus analog instrumentation recorder tape abounded during the 1960's and 1970's, but surplus sources for it have significantly diminished. Most of the audio tape that resulted from sltting surplus tape used analog instrumentation tape. So my point is: an honest surplus dealer won't touch surplus digital tape with a ten-foot pole, so there is effectively no market for it. Then again, there are dishonest surplus dealers... <> Larry Lippman @ Recognition Research Corp., Clarence, New York <> UUCP: {allegra|ames|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry <> VOICE: 716/688-1231 {hplabs|ihnp4|mtune|seismo|utzoo}!/ <> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"
jeffj@sfsup.UUCP (J.S.Jonas) (10/12/87)
[] In article <2093@kitty.UUCP>, larry@kitty.UUCP writes: > In article <2166@sfsup.UUCP>, jeffj@sfsup.UUCP (J.S.Jonas) writes: > > > Our Environmental department asked me if there is anything they need > > > to be concerned with regarding the disposal of a large number of > > > 700' and 2400' reels of magnetic tape. > > > > If you are concerned about environmental impact, why not erase them > > and sell them to a surplus place (or at least donate them to a college). > > You can bulk erase them if you are concerned about security. > > Hasn't your Environmental department heard of recycling and the > > surplus market? > > The truth of the matter is that computer tape designed for digital > recording makes a rather unsatisfactory audio tape. Not that 1/2 inch > computer tape slit to audio size won't work, mind you, but the audio > quality will be poor. The reason is that .... I agree that digital tapes are not audio tapes, but I didn't either directly nor indirectly say that they should be used in any way contrary to their intended purpose. I haven't seen the original poster comment on the condition of the tapes. If they are still useable, then there must be somewhere where tapes are sorely needed, such as a college where many backups are made but rarely used, and few projects deserve 'the good stuff'. Case in point: as an undergrad, I kept a few tapes of my stuff off-line to conserve disk space. The tapes saw little use, and now are quite unimportant. I couldn't see it worth my spending a few bucks for new tape, so a box of surplus tapes would've been very helpful then (I used old tapes because I was too cheap). Just trying to match a need with an excess. Jeffrey Jonas [ihnp4 | allegra} attunix ! jeffj
john@frog.UUCP (John Woods, Software) (10/16/87)
In article <2093@kitty.UUCP>, larry@kitty.UUCP (Larry Lippman) writes: > In article <2166@sfsup.UUCP>, jeffj@sfsup.UUCP (J.S.Jonas) writes: > > > Our Environmental department asked me if there is anything they need > > > to be concerned with regarding the disposal of a large number of > > > 700' and 2400' reels of magnetic tape. > > If you are concerned about environmental impact, why not erase them > > and sell them to a surplus place (or at least donate them to a college). > > The truth of the matter is that computer tape designed for digital > recording makes a rather unsatisfactory audio tape. ... > So my point is: an honest surplus dealer won't touch surplus > digital tape with a ten-foot pole, so there is effectively no market for > it. At MIT, my computer center used surplus DIGITAL tape in our computers all the time. What are you talking about? (We also occaisionally used them for constructing swings in the computer room when they failed to pass "tptest" :-). -- John Woods, Charles River Data Systems, Framingham MA, (617) 626-1101 ...!decvax!frog!john, ...!mit-eddie!jfw, jfw@eddie.mit.edu "Cutting the space budget really restores my faith in humanity. It eliminates dreams, goals, and ideals and lets us get straight to the business of hate, debauchery, and self-annihilation." -- Johnny Hart