Is a tea tree mattress safe for a bassinet?

Red Nose recommends that a mattress for a cot or bassinet is firm, clean, well-fitting & flat (not tilted or elevated)
A soft mattress or sleeping surface can increase the risk of sudden unexpected infant death if baby rolls over onto the tummy.
https://rednose.org.au/article/what-is-a-safe-mattress

Product Safety has the following information about bassinet mattress
Ensure the mattress fits well and is firm, smooth and no more than 75 mm thick.
https://www.productsafety.gov.au/products/babies-kids/kids-furniture/bassinettes

I used ti tree matress and pillow in bassinet, and later in cot used pillow of a larger size. 
These items were used for 4 babies and I would highly recommend them.
The new idea of babies to lay on back to sleep is so dangerous because if they vomit can choke.
It was always wrap your baby and lay on side even to use a rolled up cloth nappy to place behind the baby so it cant roll onto its back.
Turn baby from side to the other every time you place down.
The ti tree pillow is great also if bub needs it under head and tummy for releif for a short time. 
Personally I am so glad I had these ti tree pillows and the bassinet matress.  They were fantastic in hot of cold weather.  I aired them regularly.

Thank you for your recent comment to Red Nose about tea tree mattresses &infant; sleeping position.
Red Nose recommends that baby is placed on their back for sleep on a firm, well-fitting mattress that is flat not elevated.
As there are no mandatory standards in Australia for bassinets Red Nose recommends using a cot that meets standards for baby to sleep in.
These recommendations are a result of years of research internationally which has provided these evidence based recommendations.
As a result, since the late 1980’s there has been an 85% reduction in infant death rates.

Red Nose has the following information:

There is now conclusive evidence from many countries that sleeping babies prone significantly increases the risk of SUDI (In the late 1980s a peak in SIDS rates prompted several large scale case-controlled studies in a number of countries. These world-wide epidemiological studies consistently identified prone sleeping as the major risk factor for SIDS. ………In Australia, the recommendation that babies should not be slept prone was made in 1991. In 1997 a second expert group recommended that babies be placed on the back to sleep and stressed that propping of babies on their sides should be avoided. 

Since the recommendation of putting babies on their back to sleep there has been, a rapid decline in SIDS mortality which has provided overwhelming evidence of the strong association between prone sleeping and SUDI.

Some parents and health professionals have expressed concern about back sleeping and the risk of a baby choking in this position. However, careful study of the baby airway has shown that healthy babies placed to sleep on the back are less likely to choke on vomit than prone or tummy sleeping babies.
https://rednose.org.au/article/why-back-to-sleep-is-the-safest-position-for-your-baby

https://rednose.org.au/article/what-do-the-safe-sleep-recommendations-mean

A safe mattress is one that is the right size for the cot, is firm, clean and in good condition and is placed flat (not tilted or elevated).
A soft mattress or sleeping surface can increase the risk of sudden unexpected infant death if baby rolls over onto the tummy.
https://rednose.org.au/article/what-is-a-safe-mattress

For full information & references please see links to articles above.