The main ingredient in Orange Guard is d-limonene mixed with inert ingredients.
You can easily make your own mixture :)

The only microscopic evidence of compound-related toxicity noted in the rats was nephropathy in the males. d-Limonene is one of a diverse group of hydrocarbons that has been shown to induce a unique syndrome of nephropathy in male rats following subchronic or chronic exposure. Based on a review of the literature concerning this effect (U.S. EPA, 1991), EPA's Risk Assessment Forum concluded that nephropathy in male rats that is associated with alpha- 2u-globulin accumulation in hyaline droplets is not an appropriate endpoint to determine noncancer effects potentially occurring in humans.

Female mice exposed to 1000 mg/kg/day d-limonene exhibited 5-15% lower mean body weights than their respective vehicle controls after week 28 of the study. No compound-related clinical signs of toxicity were noted in either sex. An increased incidence of multinucleated hepatocytes and cytomegaly was observed in the high-dose male mice but not in female mice. Based on the occurrence of these liver lesions, a NOAEL of 250 mg/kg/day and a LOAEL of 500 mg/kg/day can be estimated from this study in mice.

Nephrotoxicity, consisting of granular casts characteristic of alpha-2u- globulin-mediated nephropathy, was observed in male Sprague-Dawley rats administered 277, 554, or 1385 mg/kg/day d-limonene daily by gavage in 1% Tween 80 for 6 months (Tsuji et al., 1975). These lesions were not observed in the female rats similarly exposed.



The developmental toxicity of d-limonene has been investigated in mice and rabbits. In the mouse study, 15 pregnant ICR mice/group were administered 0, 591, or 2363 mg/kg/day d-limonene by gavage on gestation days 7-12 (Kodama et al., 1977a). Maternal toxicity (significant reduction in body weight) and developmental toxicity (significant increase in the number of fetuses with skeletal abnormalities, including lumbar ribs, fused ribs, and delayed ossification of several bones in the paws) were observed in the animals administered 2363 mg/kg/day. No maternal or fetal effects were observed at the low dose. This study is limited in that an inadequate number of animals was used, only two doses were tested, and dosing did not continue throughout the entire period of organogenesis.

In the rabbit study, 10-18 pregnant Japanese white rabbits were administered 0, 250, 500, or 1000 mg/kg/day d-limonene by gavage on gestation days 6-18 (Kodama et al., 1977b). Exposure of does to 500 or 1000 mg/kg/day resulted in maternal toxicity. There were significant reductions in food consumption and body weight at both doses, and death also occurred in the 1000-mg/kg/day group. Developmental toxicity was not observed at any dose. This study is limited by the small sample size.

No reproductive toxicity studies have been conducted on d-limonene. Igimi et al. (1974) studied the metabolism of d-limonene after oral administration and found that about 65% of the dose was recovered in urine, feces, and expired carbon dioxide, suggesting that the majority of an oral dose is absorbed. Although it is possible that an inhaled dose would also be largely absorbed, there is no information on inhalation exposures.