I have quoted Owlcation for some of the following details.

China and India are the main sources of this grass, which can grow tall, looking like trees in a forest. It does not attract pests, so does not require treatment with pesticides. This is a massive plus for the Planet.

Britain, France, Germany, the Netherlands, and other countries in Europe have begun to cultivate bamboo. The plant is also quickly spreading to Africa and America.

In 2002, renewed cellulosic bamboo fiber was first manufactured by Hebei Jigao Chemical Fiber Co.

The cross-section of the single bamboo fiber is round with a small lumen. Bamboo fibers have a high breaking strength as well as good absorbability properties, but they have low elongation.

The main components of bamboo are cellulose, heme-cellulose, and lignin. The secondary components of bamboo are resins, wax, and inorganic salts. Bamboo contains other organic components in addition to cellulose and lignin. It contains about 2% oxidant polysaccharide, 2-4% fat, 2-6% starch and 0.8-6% protein.

The bamboo carbohydrate content plays an important role in its durability. The strength of bamboo against the attack of mold and fungi is closely related to their chemical composition.

Safe Environmental Mechanical Process of making Bamboo Linen:

In mechanical processing, harvested and crushed bamboo wood is initially treated with natural enzymes that break down bamboo into a soft material. Next, natural fibers can be mechanically combed to obtain individual fibers, followed by yarn spinning. The fabric manufactured through this process is often called bamboo linen, and this process is considered environmentally friendly because no harmful chemicals are used.

But Bamboo woven with cotton can produce an attractive fabric. See here.

Extract:

Super soft 100% organic double cloth bamboo cotton blend – the warp is cotton, the weft is bamboo. It is made by weaving two layers of cloth simultaneously, with a third binding weft to create the squares that hold the two layers together. It is a lovely breathable fabric perfect for adults and babies alike. The bamboo adds a silkiness to the touch and look of the fabric and makes this fabric very luxurious for shirts, dresses, tops and loungewear. You could also use it for pillowcases and quilt backing. Please note that the weave will appear skewed due to rolling but washing will straighten it out.

52% GOTS certified organic cotton (warp) 48% organic bamboo (weft).

The Chemical Process is not good for the environment. The bamboo cellulose is used to make all types of rayon, including viscose, modal, and lyocell.

The viscose manufacturing process is summed up in five steps:

1. The plant is chipped into a wood pulp and dissolved chemicals like sodium hydroxide, forming a brown wood pulp solution. (The hazard of sodium hydroxide for the environment is caused by the hydroxide ion (pH effect). A high concentration in water will result in toxic effects for aquatic organisms e.g. fish.)
2. This brown wood pulp is then washed, cleaned, and bleached. (Bleach also puts wildlife at risk; its byproducts have been linked to cancer in studies on laboratory animals. Environmental toxins created by bleach have lowered the populations of several species of birds and fish. Bleach is especially damaging to the environment because it lingers for many years.)
3. To create the fibers, the pulp is treated with carbon disulfide and then dissolved in sodium hydroxide to create the solution referred to as “viscose.”(Acute (short-term) inhalation exposure of humans to carbon disulfide has caused changes in breathing and chest pains. Nausea, vomiting, dizziness, fatigue, headache, mood changes, lethargy, blurred vision, delirium, and convulsions have also been reported in humans acutely exposed by inhalation.)
4. The viscose solution is forced through a spinneret, which is a machine that creates filaments, called regenerated cellulose.
5. This regenerated cellulose is spun into yarn, which can then be woven or knit into viscose rayon fabric.

But most of that clothing has historically been made from viscose rayon, which is created from bamboo or wood pulp processed in a toxic soup of chemicals that generates significant pollution. Today, a lot of experts believe that the “bamboo” label on rayon clothing is fundamentally a misrepresentation.

The main suppliers of viscose, rayon and the like are in China and India, and toxic processes are common in these countries, the sacrifice of the labour force to boost the economy is a priority. It follows the pattern of the Industrial Revolution, despite clear understanding of what the harm to the environment has been, and the legacy remains. Hebei Jigao Chemical Fiber Co. remains the leading supplier.

Lyocell is a type of Rayon made using the Lyocell process. It is a semi-synthetic fabric made using wood or bamboo cellulose

Rayon was the first manufactured fiber, developed in the late 19^th century and commercially produced in the US starting in 1910. It was originally marketed as artificial silk due to its softness, nice drape, and luster. It quickly rose in popularity because its price point was significantly lower than silk and cotton.

According to the European Man-Made Fibres Association (CIRFS), in 2016 manufactured cellulosic made up 6.6% of the global market, roughly 5.3 million metric tons. The Textile Exchange estimated that viscose made up 91% of cellulosic production, only 29% of which was sourced sustainably. (Followed by lyocell at 6% and modal at 3%.)

Rayon can have significant negative impacts on people, the environment, and biodiversity along its lifecycle. The wood pulp used to make rayon can be sustainably harvested, but often it isn’t. According to Canopy Planet, roughly a third come from ancient and endangered forests.

However, such is the attractiveness of Viscose made with Bamboo there are companies working hard to assure us they are minimising the chemical harm to the environment, and offsetting the carbon footprint by growing bamboo plantations and not adding to deforestation for the wood pulp. One of these companies is BAM. There is no doubt they have put a great deal of effort into reassuring us of their green credentials.

Rayon fabrics like Bamboo and Cupro (made from a bi-product of the cotton plant, cotton linters) are often incorrectly marketed as sustainable because the raw material is sustainably harvested (bamboo grows quickly without chemicals and a lot of water, and cotton linters are often called “waste” from cotton production despite having their own market). The production of fabric from these materials can be done in a more sustainable manner, but usually it still goes through the chemical-intensive and polluting viscose process- so be wary and really vet your sources. (Cuprammonium rayon is no longer made in the US because its producers could not meet air- and water-quality requirements.) See Bamboo.

Rayon production is dangerous for workers

• Workers can be seriously harmed by the chemicals used to make most rayon. Carbon disulfide in particular can cause reproductive harm and damage to the nervous system (carbon-disulfide-based viscose is no longer made within the U.S.). Sodium hydroxide, also known as lye, can cause corrosion and chemical burns to workers who handle it frequently and without protection.
• Also, work accidents can occur from explosions or leakages in chemical storage areas.
• According to Paul D. Blanc, who teaches occupational and environmental medicine at the University of California, San Francisco, and wrote Fake Silk: The Lethal History of Viscose Rayon, throughout most of the 20th century, viscose rayon manufacturing was inextricably linked to widespread, severe and often lethal illness among those employed in making it. For workers in viscose rayon factories, poisoning caused insanity, nerve damage, Parkinson’s disease, and increased risk of heart disease and stroke.

Do you want to wear a garment which has been processed in such a way that a fellow human being has suffered illnesses as a direct result of their labour? Read more here.

It is not easy to find clothing which has not caused health issues when being created and sewn in factories. It is up to each of us to take responsibility and search for items which we know caused NO HARM.