DCHAS-L Archives Dec 10 2010 - Re: Chemical Safety and Lab Animals

Many questions, let's see what I can do. None of this should=A0be proprieta ry since it's based on NTP requirements and their guidance. =A0 Q: In terms of the bedding handling, how do you treat the bedding?=A0 As ha zardous waste if it is a hazardous chemical?=A0 Is only the first cage chan ge after drug administration treated as hazardous? =A0 A: Of course the bedding will have excreted unchanged chemical and metaboli tes in it from the animals' feces and urine, but not in high concentrations . Unless you're dealing with something on the TCLP list and substantial dos es, it should not qualify as RCRA-regulated. However, I wouldn't just flush it or toss it out. We (and others) send it for incineration at a pathologi cal incinerator assuming it is=A0similar to hospital chemotherapy wastes th at can be similarly managed. Once the animals have been dosed, all of their used bedding is sent for incineration, as are any carcasses and body parts requiring disposal. =A0 Q:=A0Do the staff ever wear more than nitrile gloves, goggles, lab coats? =A0 A: It's complicated. During dosing, the gloves used are selected based on c hemical resistance to the test article and vehicle. After dosing, latex or nitrile is worn. Clothing is a=A0full body Tyvek suit over scrubs at all ti mes after animals have been dosed, though for short-term acute studies we h ave allowed Tyvek or equivalent lab coats over scrubs for procedures not in volving dose adminstration. Head covers and shoe covers over facility-dedic ated shoes are requred at all times. Half-face or full-face air-purifying r espirators (or PAPRs if desired) with combination cartridges are required d uring and for at least 1 hour after dose administration on acute studies, a nd at all times in the animal room after first dose admin for all dosed-fee d and chronic studies. The outer layer of PPE is discarded and personnel ch ange into=A0street clothes before leaving the facility. Those working on ch ronic studies and all studies involving dosed feed must shower out, as must animal care staff who perform cage dumping and cage or rack wash oper ations in the "ditry" side of the facility. =A0 Q: Do they have to do the bedding change in a =A0fumehood, ducted BSC?=A0 =A0 A: Animals are transferred from dirty to clean cages inside a fume hood. Do se adminstration is always done in a=A0 fume hood as well of course. A BSC would be an acceptable alternative. Cages are dumped in a HEPA-filtered cag e dump station in the "dirty" side of the cage wash area by personnel weari ng full PPE as described above for dose administration. =A0 A: What kind of extra protection would be afforded the animal care husbandr y staff if deemed necessary (e.g., double gloves, respirators?) =A0 Q: I think the basics were covered above. I would consider, although we hav e not required, Tyvek sleeve covers to assure there is no exposed skin at t he wrist. Husbandry staff wear the PPE described above in the animal rooms and those involved in cage and rack cleaning operations do so in the "ditry " side of our facility where full PPE is required. We do have cage wash ope rators add heavy rubber gloves, heavy rubber boots=A0and a rubber apron to protect against splashing with the extremely hot water from the tunnel wash er. =A0 I've probably forgotten something in there, but hopefully didn't totally co nfuse you. I should also mention that in our case we're talking about rats and mice, though similar procedures would apply with guinea pigs, hamsters, etc. Rabbits would be more of a challenge due to the caging not providing as much of a barrier to the spread of contamination. Hope that was helpful! Randal O. Norman --0-1043838365-1292003635=:28536

Many questions, let's see what I can do. None of this should be proprietary since it's based on NTP requiremen ts and their guidance.

Q: In terms of the bedding handling, how do you treat the bedding? As haza rdous waste if it is a hazardous chemical? Is only the first cage cha nge after drug administration treated as hazardous?

A: Of course the bedding will have excreted unchanged chemical and metabolites i n it from the animals' feces and urine, but not in high concentrations. Unl ess you're dealing with something on the TCLP list and substantial doses, i t should not qualify as RCRA-regulated. However, I wouldn't just flush it o r toss it out. We (and others) send it for incineration at a pathological i ncinerator assuming it is similar to hospital chemotherapy wastes that can be similarly managed. Once the animals have been dosed, all of their u sed bedding is sent for incineration, as are any carcasses and body parts r equiring disposal.

Q: Do the staff ever wear more than nitrile gloves, goggles, lab coats?

A: It 's complicated. During dosing, the gloves used are selected based on chemic al resistance to the test article and vehicle. After dosing, latex or nitri le is worn. Clothing is a full body Tyvek suit over scrubs at all time s after animals have been dosed, though for short-term acute studies we hav e allowed Tyvek or equivalent lab coats over scrubs for procedures not invo lving dose adminstration. Head covers and shoe covers over facility-dedicat ed shoes are requred at all times. Half-face or full-face air-purifying res pirators (or PAPRs if desired) with combination cartridges are required dur ing and for at least 1 hour after dose administration on acute studies, and at all times in the animal room after first dose admin for all dosed-feed and chronic studies. The outer layer of PPE is discarded and personnel chan ge into street clothes before leaving the facility. Those working on chronic studies and all studies involving dosed feed must shower out, a s must animal care staff who perform cage dumping and cage or rack wash ope rations in the "ditry" side of the facility.

Q: Do they have to do the bedding change in a fumehood, ducted BSC?

A: Animals are transferred from dirty to clean c ages inside a fume hood. Dose adminstration is always done in a fume hood as well of course. A BSC would be an acceptable alternative. Cages are dumped in a HEPA-filtered cage dump station in the "dirty" side of the cag e wash area by personnel wearing full PPE as described above for dose admin istration.

A: What kind of extra protection would be afford ed the animal care husbandry staff if deemed necessary (e.g., double gloves , respirators?)

Q: I think the basics were covered above. I woul d consider, although we have not required, Tyvek sleeve covers to assure th ere is no exposed skin at the wrist. Husbandry staff wear the PPE described above in the animal rooms and those involved in cage and rack cleaning ope rations do so in the "ditry" side of our facility where full PPE is require d. We do have cage wash operators add heavy rubber gloves, heavy rubber boo ts and a rubber apron to protect against splashing with the extremely hot water from the tunnel washer.

I've probably forgotten something in there, but hopefully didn't totally confuse you. I should also mention that in our cas e we're talking about rats and mice, though similar procedures would apply with guinea pigs, hamsters, etc. Rabbits would be more of a challenge due t o the caging not providing as much of a barrier to the spread of contaminat ion. Hope that was helpful!

Randal O. Norman

--0-1043838365-1292003635=:28536--

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